Raised Eastern Orthodox, in his youth he converted to Calvinism and found a number of Calvinist churches in his former estates. In the 1570s he turned to Unitarianism. Disillusioned by the squabbles within the Protestant camp, in 1586 he converted with his first wife to Roman Catholicism of which he became a zealous defender. After the Union of Brest he enforced conformity on the unwilling Eastern Orthodox.
- Lev supported a political union with Muscovy in 1584-1600 and led the diplomatic mission to Moscow in 1600 that proposed the union to tzar Boris Godunov, who declined the proposal. He also participated in wars with Muscovy under rule of Stefan Batory and King of Poland and Grand Duke of Lithuania Sigismund III Vasa. He became an adviser of Sigismund III and supported his radical plans to take over the Muscovite throne.
Died July 7, 1633