In 1781, Emperor Joseph II granted a permit to establish the Greek Orthodox community of the Holy Trinity. The temple was built in 1782-1787 by architect Peter Mollner. In 1856, an Austrian businessman of Greek descent, Georg Simon von Sina, brought the architect Theophilus von Hansen from Athens and commissioned him to renovate a Greek church. This was the first Byzantine-style project of the future creator of the Houses of Parliament, the Academy of Arts and many Viennese palaces. For some time, the church was open to other Orthodox Christians and used by other Orthodox communities until they built their churches.→