By the constitutions, however, of Clarendon, enacted during the reign of Henry II., they were obliged to give their presence in parliament; but as the canon law prohibited them from assisting in capital trials, they were allowed in such cases the privilege of absenting themselves.

A practice which was at first voluntary, became afterwards a rule; and on the earl of Strafford's trial, the bishops, who would gladly have attended, and who were no longer bound by the canon law, were, yet obliged to withdraw.

It had been usual for them to enter a protest, asserting their right to sit; and this protest, being considered as a mere form, was always admitted and disregarded.

But here was started a new question of no small importance.

The commons, who were now enabled, by the violence of the people, and the necessities of the crown, to make new acquisitions of powers and privileges, insisted, that the bishops had no more title to vote in the question of the earl's pardon than in the impeachment itself.