But we are not of course to suppose that at the beginning of the third century the actual bond of union between all the Churches was a fixed confession developed into a doctrine, that is, definitely interpreted. This much was gained, as is clear from the treatise _de praescriptione_ and from other evidence, that in the communities with which Tertullian was acquainted, mutual recognition and brotherly intercourse were made to depend on assent to formulae which virtually coincided with the Roman baptismal confession. Whoever assented to such a formula was regarded as a Christian brother, and was entitled to the salutation of peace, the name of brother, and hospitality.[54] In so far as Christians confined themselves to a doctrinal formula which they, however, strictly applied, the adoption of this practice betokened an advance. The scattered communities now possessed a "lex" to bind them together, quite as certainly as the philosophic schools possessed a bond of union of a real and practical character[55] in the shape of certain briefly formulated doctrines. In virtue of the common apostolic _lex_ of Christians the Catholic Church became a reality, and was at the same time clearly marked off from the heretic sects. But more than this was gained, in so far as the Antignostic interpretation of the formula, and consequently a "doctrine," was indeed in some measure involved in the _lex_. The extent to which this was the case depended, of course, on the individual community or its leaders. All Gnostics could not be excluded by the wording of the confession; and, on the other hand, every formulated faith leads to a formulated doctrine, as soon as it is set up as a critical canon. What we observe in Irenaeus and Tertullian must have everywhere taken place in a greater or less degree; that is to say, the authority of the confessional formula must have been extended to statements not found in the formula itself.