Substrati (i.e. prostrators) were penitents of the third order, so called from the custom of prostrating themselves before the bishop or priest as soon as the sermon was ended, to receive his benediction with the imposition of hands, and be made partakers of those prayers which the congregation particularly offered to God for them; after which they were obliged immediately to depart, before the communion service. They stood until this part of the service in the nave-of the church, behind the awbo. This sort of penitents are mentioned in the Council of Nice, though no particular place is assigned them; but we may collect from Tertullian and Sozomen that their station was in this part of the church; for Tertullian (De Pudicit. c. 13), speaking of the Roman discipline, says pope Zephyrin brought penitents into the church in sackcloth and ashes, and prostrated them in the midst before the widows and presbyters, to implore their commiseration and excite their tears. They were also called Kneelers, or Genufiecientes. See Bingham, Christ, Antiq. bk. 8:ch. 5, § 3; bk. 18:ch. 1, § 5.