medieval history
Refers to the academic field or historical period of the Middle Ages, especially in European or Japanese contexts.
See also: 中世
I'm majoring in medieval history at university.
This book is an introduction to European medieval history.
古代史 is 'ancient history', covering earlier periods than 中世史.
近代史 is 'modern history', covering later periods than 中世史.
Compound of 中世 (medieval times) and 史 (history).