The new ideas he encountered here greatly influenced his life and policies. By using his rights under the Cuius regio, eius religio rule, he changed the confession of his county to Calvinism in 1593. He succeeded with this nearly eveywhere in his sphere of influence, except in a few villages in the district Bornheimerberg, which surrounded Frankfurt and the condominiums shared with the Roman Catholic archbishop-elector of Mainz. The villages in the vicinity of Frankfurt had strong ties to this (mainly) Lutheran city and a majority of the villagers just went to Lutheran services in "foreign" Frankfurt territory. Also in the condominiums Philipp Ludwig II shared with Mainz he couldn't change anything — whether his subjects had become Lutheran during the reformation or had remained Roman Catholic. With his marriage in 1596 to Katharina Belgica, third daughter of William the Silent, he gained a personal connection to one of the leading personalities of Calvinism in Europe. The introduction of Calvinism and the location of the County of Hanau-Münzenberg, at only half a day's journey away from Frankfurt with its trade fairs, made Hanau an attractive place to settle for Calvinist refugees from France and later from the Southern Netherlands. They were often wealthy traders and were attractive subjects for a ruler in need of tax revenues. In 1597 and 1604, the count and the refugees entered into two treaties which gave them a large degree of self-government and founded the "New Town" of Hanau, south to the historic mediaeval settlement. This proved to be a big success and initiated an economic growth for Hanau which lasted even into the 19th century. Both the towns, "Old Hanau" and "New Hanau" were surrounded by a modern fortification of baroque style. This proved to be a first class asset in the following Thirty Years' War (1618-1648). Philipp Ludwig II also reinstated a Jewish community in Hanau. Space was allocted for the Jews on the southern fortifications of the historic town, which was no longer needed, due to the new fortifications. This Ghetto was not part of one either town, but placed directly under the administrative control of the county. Count Philipp Ludwig II also tried to get a university for his county by founding the "Hohe Landesschule" in Hanau. It was modeled on the Herborn Academy, where he had studied himself. Even so, it did not develop into a university but still exists today as a secondary school.