Unitarianism — the Christian movement that rejected the doctrine of the Trinity — was formally founded in Transylvania in 1568, and Cluj has been its centre ever since. The current Unitarian church on Bulevardul 21 Decembrie, finished in 1796 in a sober late-baroque style, replaced an earlier medieval building.
The interior is plain by Catholic standards but the historical resonance is what matters: this is essentially the cathedral of a small worldwide denomination, which still maintains a Hungarian-language seminary in the city. The adjacent John Sigismund Unitarian High School, founded in 1557, is one of the oldest schools in the country.