AI overview
I don't have sufficient context to write an accurate overview of "668." While you've indicated it relates to a year, I would need additional information about what specifically "668" refers to (a historical event, discovery, cultural moment, etc.) to provide a factual and meaningful explanation.
AI-generated from the Wikipedia summary — may contain errors.
Article
Mosaic panel of Constantine IV (Ravenna)
Year 668 (DCLXVIII) was a leap year starting on Saturday of the Julian calendar. The denomination 668 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.