After the Gunpowder Plot, James sanctioned harsh measures to control English Catholics. In May 1606, Parliament passed the Popish Recusants Act, which could require any citizen to take an Oath of Allegiance denying the Pope's authority over the king. James was conciliatory towards Catholics who took the Oath of Allegiance, and tolerated crypto-Catholicism even at court. Henry Howard, for example, was a crypto-Catholic, received back into the Catholic Church in his final months. On ascending the English throne, James suspected that he might need the support of Catholics in England, so he assured the Earl of Northumberland, a prominent sympathiser of the old religion, that he would not persecute "any that will be quiet and give but an outward obedience to the law".