In 1788, King Frederick William II of Prussia appointed him as first director of the royal building commission in Berlin. He immediately commissioned him with a draft for the Brandenburg Gate, which was built accordingly between 1788 and 1791, replacing the earlier simple guardhouses which flanked the original gate in the Customs Wall.
In 1788, King Frederick William II of Prussia appointed him as the first director of the royal building commission in Berlin. He was assigned to create a design for the Brandenburg Gate, which was constructed between 1788 and 1791, replacing the previous guardhouses that were adjacent to the original gate within the Customs Wall.