Both Protestants and Catholics declared Servetus a “public enemy of Christendom”, a capital offense in every nation of Europe. He published a heterodox theological book entitled Christianismi Restitutio, in which he set down his theological beliefs. Arrested in Lyon to be tried by the Catholics, he escaped over the rooftops. The idea of religious “pluralism” and tolerance did not really exist (at least officially) at that time in history; Servetus was a marked man for his beliefs and teaching, though he appears to have lived an exemplary personal life. He turned up in Geneva in 1553.
The civil magistrates had the Spaniard arrested and tried for subverting public order and blasphemy. Calvin was called to testify and he counseled Servetus to repent of his heretical views. When the civil authorities condemned Servetus to be burned at the stake, Calvin remonstrated that his death should be swift. They did not heed the pastor. Servetus is considered a father of Unitarianism and there is an organization in his honor today, headquartered at his former home in Spain. In a time when hundreds of people accused of witchcraft were being executed in France, Spain, Germany and Britain and multiple thousands were being persecuted or murdered for their religious beliefs, across Europe, the one execution that occurred in Geneva has been trumpeted, and continues to be, as evidence of the intolerance and “evil hypocrite” that was John Calvin, by enemies of the Reformation.