He is traditionally said to have been beheaded on 3 December, AD 298, during the reign of Diocletian.

[3] Aurelius Agricola, deputy prefect in the Roman province in North Africa, conducted the trial.

When the death penalty was imposed on St. Marcellus, Cassian threw down his pen and declared that the sentence was unjust.

He was arrested immediately and put to death a few days later on December 3.

Saint Cassian of Tangier is the martyr mentioned by St. Prudentius (born 348) in his hymn Liber Peristephanon (De Coronis Martyrum) (Carmen IV, 45-48 [1]): "Ingeret Tingis sua Cassianum, festa Massylum monumenta regum, qui cinis gentes domitas coegit.