Evidence of the brewing Decembrist revolt compelled Nicholas to act. In the first hour of he proclaimed himself Emperor of All the Russias. By noon the civil government and most of the troops of Saint Petersburg pledged allegiance to Nicholas but the Decembrists incited three thousand soldiers in support of Constantine and took a stand on Senate Square. Nicholas crushed the revolt at a cost of 1,271 lives and became an undisputed sovereign. He ruled the empire in an authoritarian reactionary manner for 29 years.