He was mistakenly classified as a martyr in the persecution by Emperor Valerian, which did not begin until after Lucius' death.

5) for condemning the Novationists for their refusal to readmit to communion Christians who repented for having lapsed under persecution.

Lucius I's feast day is 5 March, on which date he is commemorated in the Roman Martyrology in the following terms: "In the cemetery of Callistus on the Via Appia, Rome, burial of Saint Lucius, Pope, successor of Saint Cornelius.

[4] The persecution of Valerian in which he was said to have been martyred is known to have started later than March 254, when Pope Lucius died.

This relic was brought to Roskilde around the year 1100, after Lucius had been declared patron saint of the Danish region Zealand.

According to tradition, there had been demons at large at the Isefjord at Roskilde city,[5] and as they declared that they feared nothing but Lucius' skull, this had to be brought to Denmark, whereupon peace took reign of the fjord again.