Idiosyncratic to the Milanese liturgy were the processions after Matins and Vespers to the two ancient baptisteries of St John the Baptist and St Stephen. These processions, held throughout the year except in Holy Week, were provided with a very large repertory of antiphons (psallendae). The observances are documented in the Ambrosian antiphoners, in the Manuale, and in the ordinal, but to answer some of the important questions left unanswered in these books has required a detailed analysis and comparison of evidence that is in certain respects contradictory.