Despite his rare appearances in Rome, Caesar initiated a vast programme of reforms going beyond even the scale of Sulla’s. One of them governs life even now. For – with some help from the specialist scientists he met in Alexandria – Caesar introduced into Rome what has become the modern Western system of timekeeping. The traditional Roman year was only 355 days long, and it had for centuries been the job of Roman priests to add in an extra month from time to time to keep the civic calendar in step with the natural seasons. For whatever reason – probably a combination of lack of expertise and lack of will – they had signally failed to get their calculations correct. The result was that the calendar year and the natural year were sometimes many weeks apart, with the Roman equivalent of harvest festivals falling when the crops were still growing and the climate in what was called April feeling more like February (which it was). The truth is that it is always dangerous in Republican history to assume that any given date is an accurate indication of the weather. Using Alexandrian know-how, Caesar corrected the error and, for the future, established a year with 365 days, with an extra day inserted at the end of February every four years. This was a far more significant outcome of his visit to Egypt than any dalliance with Cleopatra.

— SPQR: A History of Ancient Rome by Mary Beard (46% - 47%)