however, driven out by Habsburg conquest and settled at Ada Kaleh. The presence of Muslims in the two Danubian Principalities was also attested, centering on Turkish traders and small communities of Muslim Roma. It is also attested that, during later Phanariote rules and the frequent Russo-Turkish Wars, Ottoman troops were stationed on Wallachia's territory. Following the Crimean Khanate's conquest by the Russian Empire (1783), many Tatars there took refuge in Dobruja, especially around Medgidia. At the time, Crimean Tatars had become the largest community in the region. Nogais in the Budjak began to arrive upon the close of the Russo-Turkish War of 1806–1812, when the Budjak and Bessarabia were ceded to Russia (they settled in northern Tulcea County - Isaccea and Babadag). Khotyn, once part of Moldavia, was the birthplace of Alemdar Mustafa Pasha, who was the Ottoman Grand Vizier until 1808. Two more Grand Viziers between 1821 and 1828 came from the once Moldavian city of Bender: Benderli Ali Pasha and Mehmed Selim Pasha (nicknamed Benderli, meaning "from Bender"). Over the same period, large groups of Circassians (as many as 200,000), refugees from the Caucasian War, were resettled in the Balkans, including Northern Dobruja, by the Ottomans (localities with large Circassian populace in Northern Dobruja included Isaccea, Slava Cercheză, Crucea, Horia, and Nicolae Bălcescu). During the 1860s, a significant number of Nogais, also fleeing Russian conquest, left their homes in the Caucasus and joined in the exodus to Dobruja. Members of other Muslim communities which joined in the colonization included Arabs (a group of 150 families of fellahin from Syria Province, brought over in 1831–1833), Kurds, and Persians—all of these three communities were quickly integrated into the Tatar–Turkish mainstream. Kingdom of Romania Tatars in Tulcea County were driven out by Russian troops during the Russo-Turkish War of 1877–1878 (see Muhajir Balkan). Furthermore, after the signing of the Treaty of San Stefano, the Circassians of Dobruja and of other regions liberated from Ottoman rule were expelled, avoiding any contact between the Dobrujan Circassians and the Romanian authorities. Following the conflict and the Berlin Congress, the Romanian government of Ion Brătianu agreed to extend civil rights to non-Christians. In 1923 a monument in the shape of a small mosque was built in Bucharest's Carol Park, as sign of reconciliation after World War I. A small Turkish-speaking Muslim community resided on Ada Kaleh island in the Danube, south of the Banat, an