Complex sentence: Once an MP, Burke was required to take the oath of allegiance and abjuration, the oath of supremacy, and declare against transubstantiation: no Catholic MP in Ireland is known to have done so in the eighteenth century.
Split into simpler sentences: Once an MP, Burke was required to take the oath of allegiance and abjuration, the oath of supremacy, and declare against transubstantiation. No Catholic MP in Ireland is known to have done so in the eighteenth century.