diff --git a/backend/app/api/v1/__init__.py b/backend/app/api/v1/__init__.py
index ee7faa3..88926cc 100644
--- a/backend/app/api/v1/__init__.py
+++ b/backend/app/api/v1/__init__.py
@@ -2,10 +2,12 @@
 
 from fastapi import APIRouter
 
-from app.api.v1 import auth, persons, trees, users
+from app.api.v1 import auth, events, persons, relationships, trees, users
 
 api_router = APIRouter(prefix="/api/v1")
 api_router.include_router(auth.router)
 api_router.include_router(users.router)
 api_router.include_router(trees.router)
 api_router.include_router(persons.router)
+api_router.include_router(events.router)
+api_router.include_router(relationships.router)
diff --git a/backend/app/api/v1/events.py b/backend/app/api/v1/events.py
new file mode 100644
index 0000000..90b73c6
--- /dev/null
+++ b/backend/app/api/v1/events.py
@@ -0,0 +1,39 @@
+import uuid
+
+from fastapi import APIRouter, status
+
+from app.api.deps import CurrentUser, SessionDep
+from app.schemas.event import EventCreate, EventRead
+from app.services import event_service, tree_service
+
+router = APIRouter(prefix="/trees", tags=["events"])
+
+
+@router.post("/{tree_id}/events", response_model=EventRead, status_code=status.HTTP_201_CREATED)
+async def create_event(
+    tree_id: uuid.UUID, data: EventCreate, session: SessionDep, current: CurrentUser
+) -> EventRead:
+    tree = await tree_service.get_tree(session, viewer_id=current.id, tree_id=tree_id)
+    event = await event_service.create_event(
+        session, actor=current, tree=tree, **data.model_dump()
+    )
+    return EventRead.model_validate(event)
+
+
+@router.get("/{tree_id}/persons/{person_id}/events", response_model=list[EventRead])
+async def list_person_events(
+    tree_id: uuid.UUID, person_id: uuid.UUID, session: SessionDep, current: CurrentUser
+) -> list[EventRead]:
+    tree = await tree_service.get_tree(session, viewer_id=current.id, tree_id=tree_id)
+    events = await event_service.list_events_for_person(
+        session, viewer_id=current.id, tree=tree, person_id=person_id
+    )
+    return [EventRead.model_validate(e) for e in events]
+
+
+@router.delete("/{tree_id}/events/{event_id}", status_code=status.HTTP_204_NO_CONTENT)
+async def delete_event(
+    tree_id: uuid.UUID, event_id: uuid.UUID, session: SessionDep, current: CurrentUser
+) -> None:
+    tree = await tree_service.get_tree(session, viewer_id=current.id, tree_id=tree_id)
+    await event_service.delete_event(session, actor=current, tree=tree, event_id=event_id)
diff --git a/backend/app/api/v1/persons.py b/backend/app/api/v1/persons.py
index 8624918..913d266 100644
--- a/backend/app/api/v1/persons.py
+++ b/backend/app/api/v1/persons.py
@@ -41,3 +41,14 @@ async def list_persons(
     tree = await tree_service.get_tree(session, viewer_id=current.id, tree_id=tree_id)
     persons = await person_service.list_persons(session, viewer_id=current.id, tree=tree)
     return [PersonRead.model_validate(p) for p in persons]
+
+
+@router.get("/{tree_id}/persons/{person_id}", response_model=PersonRead)
+async def get_person(
+    tree_id: uuid.UUID, person_id: uuid.UUID, session: SessionDep, current: CurrentUser
+) -> PersonRead:
+    tree = await tree_service.get_tree(session, viewer_id=current.id, tree_id=tree_id)
+    person = await person_service.get_person(
+        session, viewer_id=current.id, tree=tree, person_id=person_id
+    )
+    return PersonRead.model_validate(person)
diff --git a/backend/app/api/v1/relationships.py b/backend/app/api/v1/relationships.py
new file mode 100644
index 0000000..dab0146
--- /dev/null
+++ b/backend/app/api/v1/relationships.py
@@ -0,0 +1,50 @@
+import uuid
+
+from fastapi import APIRouter, status
+
+from app.api.deps import CurrentUser, SessionDep
+from app.schemas.relationship import RelationshipCreate, RelationshipRead
+from app.services import relationship_service, tree_service
+
+router = APIRouter(prefix="/trees", tags=["relationships"])
+
+
+@router.post(
+    "/{tree_id}/relationships",
+    response_model=RelationshipRead,
+    status_code=status.HTTP_201_CREATED,
+)
+async def create_relationship(
+    tree_id: uuid.UUID, data: RelationshipCreate, session: SessionDep, current: CurrentUser
+) -> RelationshipRead:
+    tree = await tree_service.get_tree(session, viewer_id=current.id, tree_id=tree_id)
+    relationship = await relationship_service.create_relationship(
+        session, actor=current, tree=tree, **data.model_dump()
+    )
+    return RelationshipRead.model_validate(relationship)
+
+
+@router.get(
+    "/{tree_id}/persons/{person_id}/relationships",
+    response_model=list[RelationshipRead],
+)
+async def list_person_relationships(
+    tree_id: uuid.UUID, person_id: uuid.UUID, session: SessionDep, current: CurrentUser
+) -> list[RelationshipRead]:
+    tree = await tree_service.get_tree(session, viewer_id=current.id, tree_id=tree_id)
+    rels = await relationship_service.list_relationships_for_person(
+        session, viewer_id=current.id, tree=tree, person_id=person_id
+    )
+    return [RelationshipRead.model_validate(r) for r in rels]
+
+
+@router.delete(
+    "/{tree_id}/relationships/{relationship_id}", status_code=status.HTTP_204_NO_CONTENT
+)
+async def delete_relationship(
+    tree_id: uuid.UUID, relationship_id: uuid.UUID, session: SessionDep, current: CurrentUser
+) -> None:
+    tree = await tree_service.get_tree(session, viewer_id=current.id, tree_id=tree_id)
+    await relationship_service.delete_relationship(
+        session, actor=current, tree=tree, relationship_id=relationship_id
+    )
diff --git a/backend/app/schemas/event.py b/backend/app/schemas/event.py
new file mode 100644
index 0000000..9f6bd3d
--- /dev/null
+++ b/backend/app/schemas/event.py
@@ -0,0 +1,39 @@
+import uuid
+from datetime import date, datetime
+
+from pydantic import BaseModel, ConfigDict
+
+
+class EventCreate(BaseModel):
+    event_type: str
+    # Exactly one subject: a person or a partnership (relationship).
+    person_id: uuid.UUID | None = None
+    relationship_id: uuid.UUID | None = None
+    place_id: uuid.UUID | None = None
+    # Verbatim date string (e.g. "ABT 1850") and/or a normalized range.
+    date_value: str | None = None
+    date_start: date | None = None
+    date_end: date | None = None
+    date_precision: str | None = None
+    calendar: str = "gregorian"
+    detail: str | None = None
+    notes: str | None = None
+
+
+class EventRead(BaseModel):
+    model_config = ConfigDict(from_attributes=True)
+
+    id: uuid.UUID
+    tree_id: uuid.UUID
+    event_type: str
+    person_id: uuid.UUID | None
+    relationship_id: uuid.UUID | None
+    place_id: uuid.UUID | None
+    date_value: str | None
+    date_start: date | None
+    date_end: date | None
+    date_precision: str | None
+    calendar: str
+    detail: str | None
+    notes: str | None
+    created_at: datetime
diff --git a/backend/app/schemas/relationship.py b/backend/app/schemas/relationship.py
new file mode 100644
index 0000000..880cda4
--- /dev/null
+++ b/backend/app/schemas/relationship.py
@@ -0,0 +1,28 @@
+import uuid
+from datetime import datetime
+
+from pydantic import BaseModel, ConfigDict
+
+from app.models.enums import ParentChildQualifier, RelationshipType
+
+
+class RelationshipCreate(BaseModel):
+    type: RelationshipType
+    person_from_id: uuid.UUID
+    person_to_id: uuid.UUID
+    # Only meaningful for parent_child edges (from = parent, to = child).
+    qualifier: ParentChildQualifier | None = None
+    notes: str | None = None
+
+
+class RelationshipRead(BaseModel):
+    model_config = ConfigDict(from_attributes=True)
+
+    id: uuid.UUID
+    tree_id: uuid.UUID
+    type: RelationshipType
+    person_from_id: uuid.UUID
+    person_to_id: uuid.UUID
+    qualifier: ParentChildQualifier | None
+    notes: str | None
+    created_at: datetime
diff --git a/backend/app/services/event_service.py b/backend/app/services/event_service.py
new file mode 100644
index 0000000..dbfdb3a
--- /dev/null
+++ b/backend/app/services/event_service.py
@@ -0,0 +1,136 @@
+"""Event service. Writes require editor rights; reads go through the privacy
+engine. Every event has exactly one subject — a Person or a partnership."""
+
+import uuid
+from datetime import date
+
+from sqlalchemy import select
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from app.models.event import Event
+from app.models.person import Person
+from app.models.place import Place
+from app.models.relationship import Relationship
+from app.models.tree import Tree
+from app.models.user import User
+from app.services import privacy
+from app.services.audit import record_audit
+from app.services.exceptions import Conflict, Forbidden, NotFound
+
+
+async def _belongs_to_tree(
+    session: AsyncSession, model: type, id_: uuid.UUID, tree_id: uuid.UUID
+) -> bool:
+    row = (
+        await session.execute(
+            select(model.id).where(
+                model.id == id_, model.tree_id == tree_id, model.deleted_at.is_(None)
+            )
+        )
+    ).scalar_one_or_none()
+    return row is not None
+
+
+async def create_event(
+    session: AsyncSession,
+    *,
+    actor: User,
+    tree: Tree,
+    event_type: str,
+    person_id: uuid.UUID | None = None,
+    relationship_id: uuid.UUID | None = None,
+    place_id: uuid.UUID | None = None,
+    date_value: str | None = None,
+    date_start: date | None = None,
+    date_end: date | None = None,
+    date_precision: str | None = None,
+    calendar: str = "gregorian",
+    detail: str | None = None,
+    notes: str | None = None,
+) -> Event:
+    if not await privacy.can_edit_tree(session, user_id=actor.id, tree=tree):
+        raise Forbidden("not an editor of this tree")
+    if bool(person_id) == bool(relationship_id):
+        raise Conflict("an event needs exactly one subject: person_id or relationship_id")
+    if person_id and not await _belongs_to_tree(session, Person, person_id, tree.id):
+        raise NotFound("person not found in this tree")
+    if relationship_id and not await _belongs_to_tree(
+        session, Relationship, relationship_id, tree.id
+    ):
+        raise NotFound("relationship not found in this tree")
+    if place_id and not await _belongs_to_tree(session, Place, place_id, tree.id):
+        raise NotFound("place not found in this tree")
+
+    event = Event(
+        tree_id=tree.id,
+        event_type=event_type,
+        person_id=person_id,
+        relationship_id=relationship_id,
+        place_id=place_id,
+        date_value=date_value,
+        date_start=date_start,
+        date_end=date_end,
+        date_precision=date_precision,
+        calendar=calendar,
+        detail=detail,
+        notes=notes,
+    )
+    session.add(event)
+    await session.flush()
+    record_audit(
+        session,
+        action="create",
+        entity_type="Event",
+        entity_id=event.id,
+        tree_id=tree.id,
+        actor_user_id=actor.id,
+        after={"event_type": event_type, "person_id": str(person_id) if person_id else None},
+    )
+    await session.commit()
+    await session.refresh(event)
+    return event
+
+
+async def list_events_for_person(
+    session: AsyncSession, *, viewer_id: uuid.UUID, tree: Tree, person_id: uuid.UUID
+) -> list[Event]:
+    if not await privacy.can_view_tree(session, user_id=viewer_id, tree=tree):
+        raise Forbidden("not permitted to view this tree")
+    stmt = (
+        select(Event)
+        .where(
+            Event.tree_id == tree.id,
+            Event.person_id == person_id,
+            Event.deleted_at.is_(None),
+        )
+        .order_by(Event.date_start.nulls_last(), Event.created_at)
+    )
+    return list((await session.execute(stmt)).scalars().all())
+
+
+async def delete_event(
+    session: AsyncSession, *, actor: User, tree: Tree, event_id: uuid.UUID
+) -> None:
+    if not await privacy.can_edit_tree(session, user_id=actor.id, tree=tree):
+        raise Forbidden("not an editor of this tree")
+    event = (
+        await session.execute(
+            select(Event).where(
+                Event.id == event_id, Event.tree_id == tree.id, Event.deleted_at.is_(None)
+            )
+        )
+    ).scalar_one_or_none()
+    if event is None:
+        raise NotFound("event not found")
+    from datetime import UTC, datetime
+
+    event.deleted_at = datetime.now(UTC)
+    record_audit(
+        session,
+        action="delete",
+        entity_type="Event",
+        entity_id=event.id,
+        tree_id=tree.id,
+        actor_user_id=actor.id,
+    )
+    await session.commit()
diff --git a/backend/app/services/person_service.py b/backend/app/services/person_service.py
index 320deb1..6338f71 100644
--- a/backend/app/services/person_service.py
+++ b/backend/app/services/person_service.py
@@ -14,7 +14,7 @@ from app.models.tree import Tree
 from app.models.user import User
 from app.services import privacy
 from app.services.audit import record_audit
-from app.services.exceptions import Forbidden
+from app.services.exceptions import Forbidden, NotFound
 from app.services.privacy import Visibility
 
 
@@ -86,6 +86,32 @@ async def create_person(
     return person
 
 
+async def get_person(
+    session: AsyncSession, *, viewer_id: uuid.UUID, tree: Tree, person_id: uuid.UUID
+) -> Person:
+    if not await privacy.can_view_tree(session, user_id=viewer_id, tree=tree):
+        raise Forbidden("not permitted to view this tree")
+    person = (
+        await session.execute(
+            select(Person).where(
+                Person.id == person_id,
+                Person.tree_id == tree.id,
+                Person.deleted_at.is_(None),
+            )
+        )
+    ).scalar_one_or_none()
+    if person is None:
+        raise NotFound("person not found")
+    # Run the single person through the privacy engine (redaction lands Phase 2).
+    if (
+        await privacy.person_visibility(session, user_id=viewer_id, tree=tree, person=person)
+        == Visibility.hidden
+    ):
+        raise NotFound("person not found")
+    await _attach_primary_name(session, person)
+    return person
+
+
 async def list_persons(
     session: AsyncSession, *, viewer_id: uuid.UUID, tree: Tree
 ) -> list[Person]:
diff --git a/backend/app/services/relationship_service.py b/backend/app/services/relationship_service.py
new file mode 100644
index 0000000..129a39a
--- /dev/null
+++ b/backend/app/services/relationship_service.py
@@ -0,0 +1,121 @@
+"""Relationship service. Typed, qualified edges between two Persons in a tree.
+Writes require editor rights; reads go through the privacy engine."""
+
+import uuid
+from datetime import UTC, datetime
+
+from sqlalchemy import or_, select
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from app.models.enums import ParentChildQualifier, RelationshipType
+from app.models.person import Person
+from app.models.relationship import Relationship
+from app.models.tree import Tree
+from app.models.user import User
+from app.services import privacy
+from app.services.audit import record_audit
+from app.services.exceptions import Conflict, Forbidden, NotFound
+
+
+async def _person_in_tree(session: AsyncSession, person_id: uuid.UUID, tree_id: uuid.UUID) -> bool:
+    row = (
+        await session.execute(
+            select(Person.id).where(
+                Person.id == person_id, Person.tree_id == tree_id, Person.deleted_at.is_(None)
+            )
+        )
+    ).scalar_one_or_none()
+    return row is not None
+
+
+async def create_relationship(
+    session: AsyncSession,
+    *,
+    actor: User,
+    tree: Tree,
+    type: RelationshipType,
+    person_from_id: uuid.UUID,
+    person_to_id: uuid.UUID,
+    qualifier: ParentChildQualifier | None = None,
+    notes: str | None = None,
+) -> Relationship:
+    if not await privacy.can_edit_tree(session, user_id=actor.id, tree=tree):
+        raise Forbidden("not an editor of this tree")
+    if person_from_id == person_to_id:
+        raise Conflict("a relationship needs two different people")
+    if qualifier is not None and type is not RelationshipType.parent_child:
+        raise Conflict("qualifier only applies to parent_child relationships")
+    for pid in (person_from_id, person_to_id):
+        if not await _person_in_tree(session, pid, tree.id):
+            raise NotFound("person not found in this tree")
+
+    relationship = Relationship(
+        tree_id=tree.id,
+        type=type,
+        person_from_id=person_from_id,
+        person_to_id=person_to_id,
+        qualifier=qualifier,
+        notes=notes,
+    )
+    session.add(relationship)
+    await session.flush()
+    record_audit(
+        session,
+        action="create",
+        entity_type="Relationship",
+        entity_id=relationship.id,
+        tree_id=tree.id,
+        actor_user_id=actor.id,
+        after={"type": type.value, "from": str(person_from_id), "to": str(person_to_id)},
+    )
+    await session.commit()
+    await session.refresh(relationship)
+    return relationship
+
+
+async def list_relationships_for_person(
+    session: AsyncSession, *, viewer_id: uuid.UUID, tree: Tree, person_id: uuid.UUID
+) -> list[Relationship]:
+    if not await privacy.can_view_tree(session, user_id=viewer_id, tree=tree):
+        raise Forbidden("not permitted to view this tree")
+    stmt = (
+        select(Relationship)
+        .where(
+            Relationship.tree_id == tree.id,
+            Relationship.deleted_at.is_(None),
+            or_(
+                Relationship.person_from_id == person_id,
+                Relationship.person_to_id == person_id,
+            ),
+        )
+        .order_by(Relationship.created_at)
+    )
+    return list((await session.execute(stmt)).scalars().all())
+
+
+async def delete_relationship(
+    session: AsyncSession, *, actor: User, tree: Tree, relationship_id: uuid.UUID
+) -> None:
+    if not await privacy.can_edit_tree(session, user_id=actor.id, tree=tree):
+        raise Forbidden("not an editor of this tree")
+    relationship = (
+        await session.execute(
+            select(Relationship).where(
+                Relationship.id == relationship_id,
+                Relationship.tree_id == tree.id,
+                Relationship.deleted_at.is_(None),
+            )
+        )
+    ).scalar_one_or_none()
+    if relationship is None:
+        raise NotFound("relationship not found")
+    relationship.deleted_at = datetime.now(UTC)
+    record_audit(
+        session,
+        action="delete",
+        entity_type="Relationship",
+        entity_id=relationship.id,
+        tree_id=tree.id,
+        actor_user_id=actor.id,
+    )
+    await session.commit()
diff --git a/backend/tests/test_graph.py b/backend/tests/test_graph.py
new file mode 100644
index 0000000..9af83a0
--- /dev/null
+++ b/backend/tests/test_graph.py
@@ -0,0 +1,116 @@
+"""Events and relationships through the API."""
+
+from tests.conftest import auth, register
+
+
+async def _setup_tree_with_two_people(client, email: str):
+    token = await register(client, email)
+    h = auth(token)
+    tree_id = (
+        await client.post("/api/v1/trees", json={"name": "Graph"}, headers=h)
+    ).json()["id"]
+    parent = (
+        await client.post(
+            f"/api/v1/trees/{tree_id}/persons",
+            json={"given": "Anna", "surname": "Vogel"},
+            headers=h,
+        )
+    ).json()["id"]
+    child = (
+        await client.post(
+            f"/api/v1/trees/{tree_id}/persons",
+            json={"given": "Beth", "surname": "Vogel"},
+            headers=h,
+        )
+    ).json()["id"]
+    return h, tree_id, parent, child
+
+
+async def test_event_create_list_delete(client):
+    h, tree_id, parent, _ = await _setup_tree_with_two_people(client, "ev1@example.com")
+
+    resp = await client.post(
+        f"/api/v1/trees/{tree_id}/events",
+        json={"event_type": "birth", "person_id": parent, "date_value": "ABT 1850"},
+        headers=h,
+    )
+    assert resp.status_code == 201, resp.text
+    event_id = resp.json()["id"]
+
+    listed = await client.get(f"/api/v1/trees/{tree_id}/persons/{parent}/events", headers=h)
+    assert listed.status_code == 200
+    assert len(listed.json()) == 1
+    assert listed.json()[0]["event_type"] == "birth"
+
+    resp = await client.delete(f"/api/v1/trees/{tree_id}/events/{event_id}", headers=h)
+    assert resp.status_code == 204
+    listed = await client.get(f"/api/v1/trees/{tree_id}/persons/{parent}/events", headers=h)
+    assert len(listed.json()) == 0
+
+
+async def test_event_requires_exactly_one_subject(client):
+    h, tree_id, _, _ = await _setup_tree_with_two_people(client, "ev2@example.com")
+    resp = await client.post(
+        f"/api/v1/trees/{tree_id}/events", json={"event_type": "birth"}, headers=h
+    )
+    assert resp.status_code == 409
+
+
+async def test_relationship_create_and_list(client):
+    h, tree_id, parent, child = await _setup_tree_with_two_people(client, "rel1@example.com")
+
+    resp = await client.post(
+        f"/api/v1/trees/{tree_id}/relationships",
+        json={
+            "type": "parent_child",
+            "person_from_id": parent,
+            "person_to_id": child,
+            "qualifier": "biological",
+        },
+        headers=h,
+    )
+    assert resp.status_code == 201, resp.text
+
+    for pid in (parent, child):
+        listed = await client.get(
+            f"/api/v1/trees/{tree_id}/persons/{pid}/relationships", headers=h
+        )
+        assert listed.status_code == 200
+        assert len(listed.json()) == 1
+        assert listed.json()[0]["qualifier"] == "biological"
+
+
+async def test_relationship_validation(client):
+    h, tree_id, parent, _ = await _setup_tree_with_two_people(client, "rel2@example.com")
+    # Same person on both ends.
+    resp = await client.post(
+        f"/api/v1/trees/{tree_id}/relationships",
+        json={"type": "sibling", "person_from_id": parent, "person_to_id": parent},
+        headers=h,
+    )
+    assert resp.status_code == 409
+
+    # Qualifier on a non-parent_child edge.
+    h2, t2, p_a, p_b = await _setup_tree_with_two_people(client, "rel3@example.com")
+    resp = await client.post(
+        f"/api/v1/trees/{t2}/relationships",
+        json={
+            "type": "partnership",
+            "person_from_id": p_a,
+            "person_to_id": p_b,
+            "qualifier": "biological",
+        },
+        headers=h2,
+    )
+    assert resp.status_code == 409
+
+
+async def test_non_member_cannot_write_graph(client):
+    h, tree_id, parent, _ = await _setup_tree_with_two_people(client, "rel4@example.com")
+    other = auth(await register(client, "intruder@example.com"))
+    resp = await client.post(
+        f"/api/v1/trees/{tree_id}/events",
+        json={"event_type": "birth", "person_id": parent},
+        headers=other,
+    )
+    assert resp.status_code == 403