the forms of worship for daily and Sunday church services. The controversial new book was not welcomed by either reformers or Catholic conservatives; it was especially condemned in Devon and Cornwall, where traditional Catholic loyalty was at its strongest. In Cornwall at the time, many of the people could only speak the Cornish language, so the uniform English Bibles and church services were not understood by many. This caused the Prayer Book Rebellion, in which groups of Cornish non-conformists gathered round the mayor. The rebellion worried Somerset, now Lord Protector, and he sent an army to impose a military solution to the rebellion. The rebellion hardened the Crown against Catholics. Fear of Catholicism focused on Edward's elder sister, Mary, who was a pious and devout Catholic. Although called before the Privy Council several times to renounce her faith and stop hearing the Catholic Mass, she refused. Edward had a good relationship with his sister Elizabeth, who was a Protestant, albeit a moderate one, but this was strained when Elizabeth was accused of having an affair with the Duke of Somerset's brother, Thomas Seymour, 1st Baron Seymour of Sudeley, the husband of Henry's last wife Catherine Parr. Elizabeth was interviewed by one of Edward's advisers, and she was eventually found not to be guilty, despite forced confessions from her servants Catherine Ashley and Thomas Parry. Thomas Seymour was arrested and beheaded on 20 March 1549. Problematic succession Lord Protector Somerset was also losing favour. After forcibly removing Edward VI to Windsor Castle, with the intention of keeping him hostage, Somerset was removed from power by members of the council, led by his chief rival, John Dudley, the first Earl of Warwick, who created himself Duke of Northumberland shortly after his rise. Northumberland effectively became Lord Protector, but he did not use this title, learning from the mistakes his predecessor made. Northumberland was furiously ambitious, and aimed to secure Protestant uniformity while making himself rich with land and money in the process. He ordered churches to be stripped of all traditional Catholic symbolism, resulting in the simplicity often seen in Church of England churches today. A revision of the Book of Common Prayer was published in 1552. When Edward VI became ill in 1553, his advisers looked to the possible imminent accession of the Catholic Lady Mary, and feared that she would overturn all the reforms made during Edward's reign. Perhaps surprisingly,