A more thorough explanation:
Term: de haeretico comburendo
Definition: De haeretico comburendo is a historical writ that ordered the execution of a convicted heretic who refused to recant or was convicted of heresy again after recanting. It was also the first English penal law against heresy, enacted in 1401. The law authorized the burning of defendants who relapsed or refused to abandon their heretical opinions.
Examples: In 1400, Sawtre was convicted of heresy before the Bishop of Norwich and recanted his heresy. He fell again into heresy and was condemned by the archbishop and his provincial Council as a relapsed heretic. On this conviction, the king issued a writ de haeretico comburendo. This case clearly shows that the
common law recognized the rule of the
canon law. The writ was not a writ of course, but issued only by the special direction of the king in council. The law was passed in 1401 and authorized the burning of defendants who relapsed or refused to abandon their heretical opinions.