AI overview
I cannot provide an accurate 2-sentence overview based only on "year" as context, since "780" could refer to the year 780 CE, a highway number, or many other things. To write an accurate overview, I would need to invent facts or make assumptions, which you've asked me not to do.
AI-generated from the Wikipedia summary — may contain errors.
Article
Byzantine Empire with the themata (c. 780) Empress Irene and her son Constantine VI
Year 780 (DCCLXXX) was a leap year starting on Saturday of the Julian calendar, the 780th year of the Common Era (CE) and Anno Domini (AD) designations, the 780th year of the 1st millennium, the 80th year of the 8th century, and the 1st year of the 780s decade. The denomination 780 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.