The present letter of Siricius was probably attached to the collection at the later stage to accompany Letter 15 extra collectionem, see . Rauschen (1897: 378–381) argued that the letter was written not before 391/392. When Ambrose wrote De institutione virginum (late 391 or 392), he had not yet known about about Jovinian's claim that Mary did not remain a virgin post partu. Moreover, Jerome in the Adversum Jovinianum written in the late 392 or at the beginning of 393 says that he sent his friend Pammachius in Rome the commentarioli of Jovinianus and he says nothing about his condemnation. The Roman synod must have taken place later in 393 (see Zelzer 1997: CXXVII–CXXVIII; Liebeschuetz 2010: 336–337).