German architect. Most of his works are in Westphalia, his earliest buildings were uncomplicated churches. In 1719 he was appointed Land Surveyor of Münster by Clemens August (1700-1761), Prince Bishop of Paderborn and Münster, who encouraged him to travel, first to Würzburg where he gained further experience under Balthasar Neumann, before visiting Italy and France in order to broaden his architectural knowledge. He designed Schloss Brühl (1725-28, later much changed by Neumann and others) in Franco-German Baroque style, and the enchanting brick Rococo hunting lodge of Clemenswerth (1736-50), with a two-storey building at the centre and a ring of eight detached pavilions, one of which contained a convent and chapel. Among his most successful palaces were the Erbdrostenhof, Münster (1749-57), on a triangular urban site with a concave façade fronting the "cour d'honneur" and with a convex garden-elevation, the whole on an ingenious plan with irregularly shaped rooms. The Bishop's Palace, called the Schloss, Münster (1767-73), contained elements derived from designs by Neumann, notably the curved frontispiece and rounded corners, and made use of rose-coloured brick with stone dressing. Schlaun's own dwellings, the Rüschhaus, near Münster (1745-48), and the Schlaunhaus, Münster (1753-55), both employ brick, the former looking like a Westphalian rural farm-building with a Rococo centrepiece, and the latter with a massive two-storey rusticated arch in the middle. His Clemenskirche, Münster (1745-53) is a rotunda on a triangular site constructed on a six-pointed star of superimposed triangles, clearly influenced by Borromini's church of Sant'Ivo in Rome. //