In the 1560s many Frisans joined the revolt led by William of Orange against the Habsburg monarchy. In 1577 the province of Friesland became part of the nascent Dutch Republic, as its representatives signed the Union of Utrecht. The city of Groningen was conquered by the Dutch in 1594. Since then, membership of the Dutch Republic was perceived as a guarantee for the preservation of civil liberties. Actual power, however, was usurped by the landowning gentry. Protests against aristocratic rule led to a democratic movement in the 1780s.