He brought some priests, established the first seven parishes, and, according to Jan Długosz, even personally translated Lord's Prayer and Apostles' Creed into the Lithuanian language. New converts were baptized en masse, with little teaching, and were awarded wool shirts; the haste was later criticized at the Council of Constance. On 17 February 1387 Jogaila decreed that he would build Vilnius Cathedral and petition the pope to establish the Diocese of Vilnius, which he awarded with land possessions in Tauragnai, Labanoras, Molėtai. Two other privileges, issues on 20 February and 4 March 1387, awarded nobles who would convert to Christianity with new rights and granted Magdeburg rights to Vilnius. This served not only as an incentive for conversion but also equalized nobility rights in Poland and Lithuania. Polish–Lithuanian union Jogaila left his brother Skirgaila as his regent in Lithuania. He proved to be unpopular and Lithuanian nobility resented growing Polish influence in the state. Vytautas seized the opportunity to renew his struggle for power and the Lithuanian Civil War (1389–1392) broke out. This was resolved with the Ostrów Agreement – Vytautas became the Grand Duke of Lithuania while Jogaila retained rights of an overlord. Vytautas conducted independent internal and foreign affairs, but cooperated with Jogaila. A celebrated example of the Polish–Lithuanian cooperation was the decisive victory in the Battle of Grunwald (1410) against the Teutonic Knights. Polish–Lithuanian relations were and Vytautas's independence were formalized by the Union of Vilnius and Radom (1401) and Union of Horodło (1413). Thus the Grand Duchy of Lithuania retained its sovereignty. Only the Union of Lublin (1569) created permanent union between Kingdom of Poland and Grand Duchy of Lithuania, after which the federal state Polish–Lithuanian Commonwealth was established. Finally, the Constitution of 3 May 1791 declared that both states were one, albeit this was denounced in 20 October amendments (Reciprocal Guarantee of Two Nations). Soon, they were separated in form, but most of the 19th century they spent under Russia, although administratively separate. In the early 20th century, both established their independence and since then, they have not been together in any formal sense. Historiography Up until the discovery of the original document in 1835 in a register in the Archives of the Cracow Cathedral Chapter, the Union of Krewo was unknown. Usually, important state documents were archived at the Crown Archive. It was neither referenced in any contemporary documents nor cited by medieval historians.