Henrik Cöllen (or Heinrich Köllen), German architect, active in Sweden and Finland. He was Master of the Works at Gripsholm Castle, Södermanlands (1537-45), and at Uppsala Castle (1549-51) before leaving to build fortifications in Finland. Both castles were commissioned by King Gustav I Vasa (reg 1523-1560). Gripsholm is still essentially a medieval brick structure, with four ranges and four high cylindrical towers round a courtyard. The simple ground-plans and very thick walls were, however, adapted to contemporary conditions of war, and the castle contained cannon and barracks as well as residential suites for the royal family. At Gripsholm, Cöllen combined his knowledge of late medieval castles in eastern Germany and in the Netherlands. The castle was soon thought to be out of date, however, and at Uppsala Cöllen probably played a minor part, the bastioned façade being the work of others. //