What is the difference between chronology and a calendar?

Calendars are a more modern invention. Chronology originated around the 5th century. In documents with chronology, not only dates were recorded, but also significant events. They were a book, a collection of incidents in any time frame. Chronology was carried out in various forms. Since the 18th century, most countries have switched to the Julian calendar. Special collections of events – chronicles, contained large amounts of information. Often they were written by order of princes or noble boyars.