 The Lithuanian language survived as a peasant vernacular and also as a written language in religious use, from the publication of the Lithuanian Catechism by Martynas Mažvydas in 1547.The Ruthenian language was and remained in the Grand Duchy's official use even after the Union, until the takeover of Polish.By the Union of Lublin a unified Polish–Lithuanian Commonwealth ("Rzeczpospolita") was created, stretching from the Baltic Sea and the Carpathian mountains to present-day Belarus and western and central Ukraine (which earlier had been Kievan Rus' principalities).