Pope Pius V
Roman Catholics did not have an easy time during the reign of Elizabeth, but many of them would have agreed that things could have been much worse. Catholicism was effectively illegal, but it was for not attending church that Catholics were fined, not for simply being Catholic, and the fine applied to dissenting Puritans as well as to those of the Catholic faith.
In 1559, a 12 pence fine for refusing to go to church was created, and the loss of office for Catholic clergy refusing to take the oath of supremacy. Attendance at mass was to be punished by a fine of 100 marks, but the saying of mass, or arranging for it to be said, carried the death penalty, although Elizabeth ensured that this was never implemented before 1577 as she disliked such extremism. As far as Elizabeth was concerned, so long as Catholics behaved themselves, were loyal to her, and attended church now and then, they were free to believe what they wished. Elizabeth tried to accommodate Catholic beliefs in her religious settlement so that they could go to church without feeling guilty or disloyal to their faith, and often turned a blind eye to Catholics who had secret services in their home. There was no attempt to ruthlessly seek out Catholics, and no desire to put ordinary men and women to death simply for their faith.
It was only as the Catholic threat against Elizabeth from Europe heightened as the reign progressed, that the Elizabethan government had to take a harsher stance against Catholics than they had initially anticipated. Some of Elizabeth's ministers, such as Sir Francis Walsingham, were zealously committed to the Protestant cause and wished to persecute Catholics in England, but their ambitions were always held in check by the Queen. For the first decade of the reign, the Catholics suffered little. It was not until the Papal Bull of 1570 that the situation changed.
The new pope, Pius V, did not like Elizabeth. Like all Catholics, he believed she was illegitimate, and thus had no right to the throne of England. Catholics believed that the true Queen of the land was Mary Queen of Scots. In 1570 he issued a bull "Regnans in Excelsis" (a papal document) against Elizabeth, that excommunicated her and absolved all her subjects from allegiance to her and her laws. This was a drastic step, and one that was not approved of by Philip II of Spain, or some English Catholics, who knew that this would make things difficult for Catholics in England. Excommunication was a great disgrace to Catholics. An excommunicated person was not to be dealt with, as it was believed that they were unchristian and would go to hell.