By the 17th century, the east part of the Wild Fields had been settled by runaway peasants and serfs who made up the core of the Cossackdom. During the Bohdan Khmelnytsky Uprising the north part of this area was settled by Cossacks from the Dnieper basin and came to be known as Sloboda Ukraine. After a series of Russo-Turkish wars waged by Catherine the Great, the area formerly controlled by the Ottomans and the Crimean Tatars was incorporated into the Russian Empire in the 1780s. The Russian Empire built many of the cities in the Wild Fields, including Odessa, Sevastopol, Yekaterinoslav, and Nikolayev. Most of Kiev was also built during this time. The area was filled with Russian and Ukrainian settlers and the name "Wild Fields" became outdated; it was instead referred as New Russia (Novorossia). According to the "Historical Dictionary of Ukraine", "The population consisted of military colonists from hussar and lancer regiments, Ukrainian and Russian peasants, Cossacks, Serbs, Montenegrins, Hungarians, and other foreigners who received land subsidies for settling in the area."