Stanley Mordaunt Leathes, The Cambridge Modern History, Volume 2… (1904)
“ The reign of Sigismund Augustus (1548-72) saw the Polish Reformation at its height. The Synod of Piotrkow in 1552, at which Stanislaus Hosius, the Bishop of Ermland, first took a prominent part as a defender of the Church, initiated a vigorous campaign against the Reform; but although the clergy procured the martyrdom of a poor priest, they found themselves helpless against the nobles. The Diet of 1552 left to the clergy the power of judging heresy, but deprived them of the authority to inflict any civil or political penalty. ”
