It's quite common in older houses to have the same breaker supply both lights and receptacles in a bedroom, and possibly other nearby rooms. So most likely the breaker that tripped controlled all of them.

Unless there is something else that you haven't explained.

Breakers trip from over current. Sounds like you have fault in the light circuit or more likely the fixture.

If this is a newer home with AFCI breaker it could have been a false trip. Did you try to reset the breaker? What happened?