old master
US /ˌoʊld ˈmæs.tər/
UK /ˌoʊld ˈmæs.tər/

1.
a distinguished European painter of the period from about 1300 to 1800
:
•
The museum acquired a rare painting by an Old Master.
•
She specializes in the restoration of Old Master drawings.
a distinguished European painter of the period from about 1300 to 1800