46 BC was 445 days long and is the longest year in human history.

Year 46 BC was the last year of the pre-Julian Roman calendar. At the time, it was known as the Year of the Consulship of Caesar and Lepidus (or, less frequently, year 708 Ab urbe condita). The denomination 46 BC 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.