Bartholomaeus Madauer was born in M?nster and installed as Abbot of the Monastery of Aldersbach (near Passau) in 1552. There he made a number of chalice sundials and devices for determining the planetary rulers of the hours. He often signed his instruments with the initials 'AB' (Abbas Bartholomaeus). Bartholomaeus Madauer remained abbot until 1577, when he moved to Passau where he died on 25 August 1579.
Chalice Dial, Signed by Bartholomaeus Madauer, Aldersbach, Dated 1554 (London, BM)