but louis duchesne in his "origines du culte chrétien" put forward a theory of origin which works out very clearly, though it is almost all founded on conjecture and a priori reasoning. he rejects entirely the ephesine supposition, and considers that the orientalisms which he recognizes in the hispano-gallican rite are of much later origin than the period of st. irenæus, and that it was from milan as a centre that a rite, imported or modified from the east, perhaps by the cappadocian arian bishop auxentius (355-374), the predecessor of st. ambrose, gradually spread to gaul, spain, and britain. he lays great stress on the important position of milan as a northern metropolis, and on the intercourse with the east by way of aquileia and illyria, as well as on the eastern nationality of many of the bishops of milan. in his analysis of the gallican mass, duchesne assumes that the seventh-century bobbio sacramentary (bibl. nat., 13,246), though not actually milanese, is to be counted as a guide to early ambrosian usages, and makes use of it in the reconstruction of the primitive rite before, according to his theory, it was so extensively romanized as it appears in the earliest undeniably ambrosian documents. he also appears to assume that the usages mentioned in the letter of st. innocent i to decentius of eugubium as differing from those of rome were necessarily common to milan and gubbio. paul lejay has adopted this theory in his article in the "revue d'histoire et littérature religeuses" (ii, 173) and in dom cabrol's dictionnaire d'archéologie chrétienne et de liturgie" [s. v. ambrosien (rit)].