Piotr of Goniądz

For his support of unitarianism and anti-trinitarianism at the Protestant council of Secemin (22 January 1556), he was officially excommunicated by the Calvinists at the Synod of Pińczów in April of that year.

Invited to Węgrów, Piotr became the head of the local Protestant commune and one of the most notable leaders of the Calvinist community in Poland.

The radical political, ethical and religious beliefs of Piotr of Goniądz gained him much popularity among the Protestant clergy and lesser gentry, though also created many conflicts, especially with the magnates.

The members of his community, often regarded as a sect within the Calvinist church, were forbidden to hold any public office, serve in the army or even carry arms.

Among them was Doktrina pura et clara de praecepuis Christianae religionis articulus, which survived in a single copy currently held in Bibliothèque Nationale in Paris.