Short answers, pulled from the story.
The name Wallachia derives from the Germanic term walhaz used to describe Romance-speakers. Romanians preferred the denomination țara Românească meaning Romanian Country or Romanian Land.
Wallachia began to form as a principality around the 13th century following the unification of smaller political entities. Tradition holds that Radu Negru crossed the Carpathians in 1290 while Basarab I consolidated power by 1330 after the Battle of Posada.
Ottoman suzerainty over Wallachia lasted from 1417 until the mid-19th century with interruptions by rulers like Vlad the Impaler and Michael the Brave. Phanariote rule began in 1715 when Nicholas Mavrocordatos became prince after the Ottomans renounced the elective system.
Slavery existed from before the founding of the principality until it was abolished in stages during the 1840s and 1850s. The earliest law freeing state slaves appeared in March 1843 and a law from February 1856 emancipated all slaves to the status of taxpayers or citizens.
Wallachia returned a majority of anti-unionists to its divan until those elected changed their allegiance after a mass protest of Bucharest crowds. Alexander John Cuza was voted prince of Wallachia on the 5th of February 1859 effectively uniting both principalities.