The area of the present-day town has been settled since Neolithic times. The name Oschatz derives from the Sorbian word for abatis. The first written mention was in 1200 as a name "Johannes de Ozzetz", however the association to Oschatz is uncertain. The first definite mention of the town dates from 1238, as "Ozzechz" is mentioned in a document from the Henry III, Margrave of Meißen. The oldest document found in the town aarchive is an indulgence letter from Bishop Conrad of Meißen, dated 1246. In 1344 the people's army The Geharnischten certified for the association of towns Oschatz, Torgau and Grimma, and a schoolmaster was employed in 1365. A fort in Oschatz was first mentioned in 1377, and a watch tower was erected at the site of the current museum. The town received market rights in 1394.