 In 1926 Borkovský was appointed assistant to Karel Guth, Head of the Historical Archaeology Department of the National Museum and placed in charge of the museum's excavation work at Prague Castle (as part of the Prague Castle Research Commission).In 1928 Borkovský excavated the Prague Castle skeleton, a ninth-century burial.The discovery was not published at the time, as Guth controlled this aspect and was often late with his articles; the skeleton would however play a key part in Borkovský's later career.