46 BC sync with the solar year but had missed a few with the chaos of the civil wars of the late republic. Julius Caesar added two extra leap months to recalibrate the calendar in preparation for his calendar reform, which went into effect in 45 BC. This year therefore had 445 days, and was nicknamed "annus confusionis" ("year of confusion"). <onlyinclude> </onlyinclude> 46 BC 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
Calendar as the week. Because the number of days in the "tropical year" is not a whole number, a solar calendar must have a different number of days in different years. This may be handled, for example, by adding an extra day in leap years. The same applies to months in a lunar calendar and also the number of months in a year in a lunisolar calendar. This is generally known as intercalation. Even if a calendar is solar, but not lunar, the year cannot be divided entirely into months that never vary in length. Cultures may define other units of