In 1589, when Henry Julius succeeded his father as ruler of Brunswick-Wolfenbüttel, he replaced Saxon by Roman Law, and instead of local nobles, lawyers with academic degrees now served as judges. He was also versed in architecture and began to rebuild his Wolfenbüttel residence in a lavish Weser Renaissance style, including the construction of the Protestant "Beatae Mariae Virginis" main church which started in 1608. He also had had extended baracks, walls and fortifications laid out around the city. He invited Hans Vredeman de Vries to develop ramparts and had a canal built through a swampland between Hornburg and Oschersleben. One of the most important buildings erected under his rule was the "Juleum Novum", the main lecture hall of the Helmstedt university. However, he lost control of the state's finances and amassed large amounts of public debt. When the rights of the nobles were reduced, the local nobles sued Henry Julius at the "Reichskammergericht" (Imperial Court) in Speyer. A compromise was struck in 1601.