 Linde faced difficulties in organizing the school, and with Prussian authorities who insisted on German as the language of instruction.Following Napoleon's victory over Prussia, in 1807 Warsaw became the capital of the Duchy of Warsaw.With Linde continuing as the Lyceum's director, the school was now modeled after the French system, while Polish replaced German as the primary language of instruction at the "Liceum Warszawskie" (Warsaw Lyceum).