The
Polish Brethren (Polish:
Bracia Polscy) were members of the
Minor Reformed Church of Poland, a
Nontrinitarian Protestant church that existed in
Poland from 1565 to 1658. By those on the outside, they were called "
Arians" or "
Socinians" (,
), but themselves preferred simply to be called "Brethren" or "Christians," and, after their expulsion from Poland, "
Unitarians".