AI overview
I don't have enough context to write an accurate overview. The word "661" could refer to many different things (a year, a route, a code, etc.), and you've only provided "year" as context. Could you clarify what specifically you're asking about regarding 661?
AI-generated from the Wikipedia summary — may contain errors.
Article
Expansion of the caliphate under the Umayyads: Expansion under Muhammad, 622–632 Expansion during the Rashidun Caliphate, 632–661 Expansion during the Umayyad Caliphate, 661–750
Year 661 (DCLXI) was a common year starting on Friday of the Julian calendar. The denomination 661 for this year has been used since the early medieval period, when the Anno Domini calendar era became the prevalent method in Europe for naming years.