People mostly remember Caesar as a ruler, however in 63 BC (5 years before the Gallic wars) Caeser managed to get himself elected as Pontifex Maximus (chief high priest).

Adjusting the calendar was as part of the duties of the Pontifex Maximus. They decided public holidays and they decided whether to add an "intercalary month" (at the end of February which used to be the last month).

There are many interesting things to say about this but since this is hacker news I'm going ro focus on one:

Caesar was away campaigning a lot and the Pontifex could adjust the calendar only while physically in Rome. So many years went by without calendar fixes.

After having benefited from the confusion and the edge he had by understanding the calendar (like knowing he could safely cross the Adriatic when his opponent assumed that crossing it that given month was a bad luck) he decided to fix the calendar so that it doesn't require a human in the loop.

In a way, he automated himself out of his job.