Commonly, from the perspective of art history, the term until around A.D. 894 (the year that the dispatch of the Japanese envoy to Tang-dynasty China was ended) is called the Heian period's former half, and the term after the year is called the Heian period's latter half (or the Fujiwara period).
美術史では、遣唐使が廃止された894年あたりを境にして、以前を平安時代前期、以後を平安時代後期（藤原時代）と呼ぶことが多い。