to note whether the two thrones could not be occupied by the same person, allowing Partida Națională to introduce the candidacy of Alexandru Ioan Cuza in both countries. On January 17 (January 5, 1859, Old Style), in Iași, he was elected prince of Moldavia by the respective electoral body. After street pressure over the much more conservative body in Bucharest, Cuza was elected in Wallachia as well (February 5/January 24), this being considered as the day of the unification of Moldavia and Wallachia by means of a personal union. In 1862, after diplomatic missions that helped remove opposition to the action, the United Principalities (the basis of modern Romania) was formally created, and instituted Cuza as Domnitor – thus officially ending the existence of the Principality of Moldavia. All other pending legal matters were clarified after the replacement of Cuza with Carol of Hohenzollern-Sigmaringen in April 1866, and the creation of an independent Kingdom of Romania in 1881. Society Aristocracy Nobility Ranks and titles Commoner Obște Taxes Law Vlach law (common law) Byzantine law Organic Statute (1831–1858) Slavery Slavery () was part of the social order from before the founding of the Principality of Moldavia, until it was abolished in stages during the 1840s and 1850s. Most of the slaves were of Roma (Gypsy) ethnicity. There were also slaves of Tatar ethnicity, probably prisoners captured from the wars with the Nogai and Crimean Tatars. The institution of slavery was first attested in a 1470 Moldavian document, through which Prince Stephen the Great frees Oană, a Tatar slave who had fled to Jagiellon Poland. The exact origins of slavery are not known, as it was a common practice in medieval Europe. As in the Byzantine Empire, the Roma were held as slaves of the state, of the boyars or of the monasteries. Historian Nicolae Iorga associated the Roma people's arrival with the 1241 Mongol invasion of Europe and considered their slavery as a vestige of that era; he believed that the Romanians took the Roma as slaves from the Mongols and preserved their status to control their labor. Other historians consider that the Roma were enslaved while captured during the battles with the Tatars. The practice of enslaving prisoners may also have been taken from the Mongols. The ethnic identity of the "Tatar slaves" is unknown, they could have been captured Tatars of the Golden Horde, Cumans, or the slaves of