diff --git a/ical/event.py b/ical/event.py
index 2a5a39e..a729bee 100644
--- a/ical/event.py
+++ b/ical/event.py
@@ -27,7 +27,7 @@
 
 from .alarm import Alarm
 from .component import ComponentModel, validate_until_dtstart, validate_recurrence_dates
-from .iter import RulesetIterable
+from .iter import RulesetIterable, as_rrule
 from .exceptions import CalendarParseError
 from .parsing.property import ParsedProperty
 from .timespan import Timespan
@@ -362,16 +362,7 @@ def as_rrule(self) -> Iterable[datetime.datetime | datetime.date] | None:
 
         This is only valid for events where `recurring` is True.
         """
-        if not self.rrule and not self.rdate:
-            return None
-        if not self.start:
-            raise CalendarParseError("Event must have a start date to be recurring")
-        return RulesetIterable(
-            self.start,
-            [self.rrule.as_rrule(self.start)] if self.rrule else [],
-            self.rdate,
-            self.exdate,
-        )
+        return as_rrule(self.rrule, self.rdate, self.exdate, self.dtstart)
 
     @root_validator(pre=True, allow_reuse=True)
     def _inspect_date_types(cls, values: dict[str, Any]) -> dict[str, Any]:
diff --git a/ical/iter.py b/ical/iter.py
index 4b62edd..caf3a35 100644
--- a/ical/iter.py
+++ b/ical/iter.py
@@ -28,6 +28,8 @@
 
 from .timespan import Timespan
 from .util import normalize_datetime
+from .types.recur import Recur
+from .exceptions import CalendarParseError
 
 __all__ = [
     "RecurrenceError",
@@ -401,3 +403,29 @@ def today(self) -> Iterator[T]:
     def now(self, tz: datetime.tzinfo | None = None) -> Iterator[T]:
         """Return an iterator containing all events active on the specified day."""
         return self.at_instant(datetime.datetime.now(tz=tz))
+
+
+def as_rrule(
+    rrule: Recur | None,
+    rdate: list[datetime.datetime | datetime.date],
+    exdate: list[datetime.datetime | datetime.date],
+    start: datetime.datetime | datetime.date | None,
+) -> Iterable[datetime.datetime | datetime.date] | None:
+    """Return an iterable containing the occurrences of a recurring event.
+
+    A recurring event is typically evaluated specially on the timeline. The
+    data model has a single event, but the timeline evaluates the recurrence
+    to expand and copy the the event to multiple places on the timeline.
+
+    This is only valid for events where `recurring` is True.
+    """
+    if not rrule and not rdate:
+        return None
+    if not start:
+        raise CalendarParseError("Event must have a start date to be recurring")
+    return RulesetIterable(
+        start,
+        [rrule.as_rrule(start)] if rrule else [],
+        rdate,
+        exdate,
+    )
diff --git a/ical/journal.py b/ical/journal.py
index 09ddcb4..4e74fc7 100644
--- a/ical/journal.py
+++ b/ical/journal.py
@@ -28,7 +28,7 @@
 )
 from .exceptions import CalendarParseError
 from .util import dtstamp_factory, normalize_datetime, uid_factory, local_timezone
-from .iter import RulesetIterable
+from .iter import RulesetIterable, as_rrule
 from .timespan import Timespan
 
 
@@ -156,16 +156,7 @@ def as_rrule(self) -> Iterable[datetime.datetime | datetime.date] | None:
 
         This is only valid for events where `recurring` is True.
         """
-        if not self.rrule and not self.rdate:
-            return None
-        if not self.start:
-            raise CalendarParseError("Event must have a start date to be recurring")
-        return RulesetIterable(
-            self.start,
-            [self.rrule.as_rrule(self.start)] if self.rrule else [],
-            self.rdate,
-            [],
-        )
+        return as_rrule(self.rrule, self.rdate, self.exdate, self.dtstart)
 
     _validate_until_dtstart = root_validator(allow_reuse=True)(validate_until_dtstart)
     _validate_recurrence_dates = root_validator(allow_reuse=True)(
diff --git a/ical/todo.py b/ical/todo.py
index 337fa8e..c5dd5fa 100644
--- a/ical/todo.py
+++ b/ical/todo.py
@@ -24,7 +24,7 @@
 from .alarm import Alarm
 from .component import ComponentModel, validate_until_dtstart, validate_recurrence_dates
 from .exceptions import CalendarParseError
-from .iter import RulesetIterable
+from .iter import RulesetIterable, as_rrule
 from .parsing.property import ParsedProperty
 from .timespan import Timespan
 from .types import (
@@ -279,16 +279,9 @@ def as_rrule(self) -> Iterable[datetime.datetime | datetime.date] | None:
         """
         if not self.rrule and not self.rdate:
             return None
-        if not self.start:
-            raise CalendarParseError("Event must have a start date to be recurring")
         if not self.due:
             raise CalendarParseError("Event must have a due date to be recurring")
-        return RulesetIterable(
-            self.start,
-            [self.rrule.as_rrule(self.start)] if self.rrule else [],
-            self.rdate,
-            self.exdate,
-        )
+        return as_rrule(self.rrule, self.rdate, self.exdate, self.dtstart)
 
     @root_validator
     def _validate_one_due_or_duration(cls, values: dict[str, Any]) -> dict[str, Any]: