 In particular, the Ides were late (on the 15th rather than 13th) in March, May, July and October, showing that these months always had 31 days in the Roman calendar, whereas Sacrobosco's theory requires that March, May and July were originally 30 days long and that the length of October was changed from 29 to 30 days by Caesar and to 31 days by Augustus.Further, Sacrobosco's theory is explicitly contradicted by the 3rd and 5th century authors Censorinus and Macrobius, and it is inconsistent with seasonal lengths given by Varro, writing in 37 BC, before Sextilis was renamed for Augustus in 8 BC, with the 31-day Sextilis given by an Egyptian papyrus from 24 BC, and with the 28-day February shown in the "Fasti Caeretani", which is dated before 12 BC.The Julian calendar has two types of year