How can historians know the dates of things so specifically?

Question

Example: Historians can know when the Jewish Temple was destroyed, when certain Pharaohs reigned, when the Gallic wars occurred, etc.

In: Other

Answer 1

The Romans dated years by the names of the two consuls that year. Caesar, for example, begins his *Commentaries* with the year “Marcus Messala and Marcus Piso were consuls”. Since we have pretty complete records from that time, we know that’s 61 BC.

Pharaohs are a bit different. We have complete “kings lists” the dynasties, which tell us the order and length of each pharaoh’s reign. But we don’t have a date to anchor those relative years. The Old Dynasty begins somewhere in the 27th Century BC, but if you read specific years, they’re just estimates.