 Complete the following phrase:  Around 1498, Joseph Bolharynovich, Metropolitan of Kiev, and Wojciech Tabor, Bishop of Vilnius, attempted to persuade Helena to support a church union as it was envisioned at the Council of Florence  the Orthodoxs would retain their traditions, but would accept the pope as their spiritual sovereign. Helena refused, but Ivan III used it as one of casus belli when he renewed the war with Lithuania in May 1500. At the time Poland, Lithuanias ally, was engaged in the PolishOttoman War 14841504 and could not offer assistance. The Muscovite army scored victories in the 