What religion were England in 1625?

In 1625, the King was Charles I. He was of the Stuart lineage and Protestant. There was still much tension between Protestant and Catholic churches and persecution was commonplace. No lasting settlement was reached until James II converted to Catholicism, fathered a son in the Catholic faith and was usurped by Parliament in 1688. William III became King in that year on the strength of his wife's descent from the Stuart line and they reigned as joint monarchs. Being a Dutchman, he was not Catholic (which is what Parliament wanted) but nor was he an adherent to the Church of England - so forced Parliament to pass an Act which permitted freedom of worship (including Catholics). This came to a final settlement in 1701, which permitted much Catholic activity - but denied them any accession to the Crown. Thus it is today that no Catholic, nor anybody married to a catholic, can become King or Queen.