 QCs were also required to take the Oath of Supremacy, which Daniel O'Connell refused as a Roman Catholic; despite being the most prominent and best paid barrister in Ireland, he was a junior counsel for 30 years until granted a patent of precedence in 1831.From the beginning, QCs were not allowed to appear against the Crown without a special licence, but this was generally given as a formality.This stipulation was particularly important in criminal cases, which are mostly brought in the name of the Crown.