According to the Liber Pontificalis, Bishop Zosimus died on 26 December AD 418, two days after the installment of the new prefect Anicius Aurelius Symmachus. Zosimus' funeral took place in the basilica of San Lorenzo fuori la mura; after the obsequies Eulalius and his followers occupied the Lateran Basilica. They were probably waiting till Sunday (29 December) to ordain Eulalius there. The presbyters opposing Eulalius gathered in the church of Theodora (unidentified) and elected the presbyter Boniface as a next bishop. Boniface was later ordained in the church of Marcellus (titulus Marcelli, today's San Marcello in Corso; the present letter is the earliest mention of the church; Liber Pontificalis sets the ordination of Boniface in the basilica of Julius).
The schism was related to Emperor Honorius by Symmachus in the letter from 29 December 418 [1298]. The emperor replied Symmachus on 3 January recognizing Eulalius as a valid bishop of Rome and ordering the exile of Boniface (see letter 15 in the Collectio Avellana). Symmachus fulfilled the orders of the emperor and Eulalius entered the basilica of St. Peter where he celebrated the Mass (see letter 16 in the Collectio Avellana). Later, however, the party of Bonifatius sent the petition [1339] to the emperor and obtained here a favourable response.