 The influence of his translations on the development of medieval European astronomy was especially large.In his own account he was born around 1100 in "central Istria", then part of the Duchy of Carinthia.The location is difficult to pin down given the much broader extent of the March of Istria in the 12th century which included the Karst Plateau, with Trieste and Duino, and most of the area of later Inner Carniola, possibly encompassing the upper Vipava Valley.