You may describe something that's specific to an area as being regional - the set containing a thing specific to Wiltshire, something else specific to Brittany, and something else specific to Moray might be described as a set of regional things.

What's the word for something that's specific to a time period, rather than a location, especially in the past? Not a given time period, just specific to any time period.

A set containing nuclear weapon use (second world war), data storage format wars (digital era), and major crusades (medieval era), might be described as being a set of \_\_\_\_ things.

"Chronodemic" feels like it should be the right word, but that doesn't appear to be a word.