Saint Cassian of Tangier was a Christian saint of the 3rd century. He is traditionally said to have been beheaded on 3 December, AD 298, during the reign of Diocletian

Diocletian

Diocletian |latinized]] upon his accession to Diocletian . c. 22 December 244  – 3 December 311), was a Roman Emperor from 284 to 305....

. The Passion of Saint Cassian is appended to that of Saint Marcellus of Tangier

Marcellus of Tangier

Saint Marcellus of Tangier or Saint Marcellus the Centurion is venerated as a Martyr Saint by the Roman Catholic Church and the Eastern Orthodox Church...

. It is, however, not considered reliable. Saint Cassian of Tangier is mentioned by Prudentius

Prudentius

Aurelius Prudentius Clemens was a Roman Christian poet, born in the Roman province of Tarraconensis in 348. He probably died in Spain, as well, some time after 405, possibly around 413...

 (born 348) in his hymn Liber Peristephanon (De Coronis Martyrum) (Carmen IV, 45-48 http://www.thelatinlibrary.com/prudentius/prud4.shtml): "Ingeret Tingis sua Cassianum,
festa Massylum monumenta regum,
qui cinis gentes domitas coegit.
ad iuga Christi."

Sources

• Vincent J. O'Malley, Saints of Africa, ed. Our Sunday Visitor Publishing, 2001, p. 164 http://books.google.com/books?id=8WQkrY95FtEC&printsec=frontcover&dq=CASSIaN+tomb+tingis&lr=&hl=nl#PPA164,M1