What significant action did Mary I take when she became the Queen of England?

When Mary I became the Queen of England in 1553, one of her first and most significant actions was to restore her nation's ties to the Catholic Church. Following the reign of her half-brother, Edward VI, England had shifted towards Protestantism, breaking away from the authority of the Pope. Mary, a devout Catholic, sought to reverse these changes and return England to Catholicism. This involved reinstating the Pope's authority over the English church and re-establishing traditional Catholic practices and beliefs that had been suppressed during the Protestant Reformation. Her efforts also led to the persecution of Protestant reformers, which earned her the nickname "Bloody Mary" due to the violent measures taken against those who resisted her reinstatement of Catholicism.