[2][3] This tradition states that Romulus became the first bishop of Fiesole and was martyred during the reign of Domitian along with four companions: Carissimus, Dulcissimus, Marchis(i)anus, and Crescentius.

[1] From then on, Romulus was considered a martyred bishop of Fiesole, and his companions were named as Carissimus, Dulcissimus, Marchis(i)anus (Marchiziano), and Crescentius.

[1] As Antonio Borrelli remarks, sometime between the end of the 10th century and the beginning of the eleventh, Romulus was "upgraded" from being considered a Confessor of the Faith to a martyr, possibly by a local abbot named Teuzo.

[2] The most ancient image depicting Romulus is a 1440 triptych in Fiesole Cathedral by Bicci di Lorenzo, where he is represented with Saints Alexander, Peter and Donatus.

[4] Also in the cathedral is a collection of frescoes by Nicodemo Ferrucci adorning the vault of the apse which depict scenes from the life of Saint Romulus.