printing of books in Lithuanian. Ruthenia After the principalities of Halych and Volhynia became integrated with the Grand Duchy, Ruthenia's nobility gradually rendered loyalty to the multilingual and cultural melting pot that was the Grand Duchy of Lithuania. Many noble Ruthenian families intermarried with Lithuanians. The rights of Orthodox nobles were nominally equal to those enjoyed by the Polish and Lithuanian nobility, but they were put under cultural pressure to convert to Catholicism. It was a policy that was greatly eased in 1596 by the Union of Brest. See, for example, the careers of Senator Adam Kisiel and Jerzy Franciszek Kulczycki. Origins of szlachta surnames The Proto-Slavic suffix "-ьskъ" means "characteristic of", "typical of". It's similar to the English suffixes "-ic" and "-ish". This suffix exists in Polish as "-ski" (feminine: "-ska"). It's attached to surnames derived from a person's occupation, characteristics, patronymic surnames, or toponymic surnames (from a person's place of residence, birth or family origin). In antiquity, the szlachta used topographic surnames to identify themselves. The expression "z" (meaning "from" sometimes "at") plus the name of one's patrimony or estate (dominion) carried the same prestige as "de" in French names such as "de Châtellerault", and "von" or "zu" in German names such as "von Weizsäcker" or "zu Rhein". For example, the family name of counts Litwiccy (Litwicki) was formed with the patronymic suffix -ic from the ethnic name Litwa, i.e. Lithuania, 'nation of Lithuanians'. It refers to the early modern empire of Central Europe, the Polish-Lithuanian Commonwealth (1569–1648). In Polish "z Dąbrówki" and "Dąbrowski" mean the same thing: "of, from Dąbrówka." More precisely, "z Dąbrówki" means owning the patrimony or estate Dąbrówka, not necessarily originating from. Almost all the surnames of genuine Polish szlachta can be traced back to a patrimony or locality, despite time scattering most families far from their original home. John of Zamość called himself John Zamoyski, Stephen of Potok called himself Potocki. At least since the 17th century the surnames/cognomens of szlachta families became fixed and were inherited by following generations, remaining in that form until today. Prior to that time, a member of the family would simply use his Christian name (e.g., Jakub, Jan, Mikołaj, etc.), and the name of the coat of arms common to all members of his clan. A member of the family would be identified as, for example, "Jakub z Dąbrówki", herbu Radwan, (Jacob to/at Dąbrówki of the knights'