Reading 21a: On the sub-prior
The abbot shall, on the advice of the prior and certain good men, instate a sub-prior, who shall diligently execute the offices of the prior, when the latter is absent. When the prior is present, he (the sub-prior) ought to carefully investigate transgressions and bring claims against the offender in chapter. He shall sit behind the abbot in the choir and in chapter. He shall grant all sorts of permission, just as the prior, in case the latter is absent; and, when there is need, he shall go out of the cloister without permission; he shall speak with whomever he may wish.