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, 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. After the Reformation, the skull was taken to the exhibition rooms of king Frederik III in Copenhagen, where it was on exhibit along with the petrified embryo a woman had carried inside her for 28 years, as well as other monstrosities the king had collected. The skull remained in Roskilde Cathedral until 1908, when it was moved to Saint Ansgar's Cathedral while the property of Copenhagen's National museum. Pope Lucius' head is among the few relics to have survived the Reformation in Denmark. However the Norwegian researcher Øystein Morten started wondering if Lucius' skull might have been mixed up with the skull of the Norwegian king Sigurd the Crusader (1090–1130). This skull had also been kept in the Danish National Museum collection in the 1800s until it was donated to Oslo University in 1867. Danish experts from the National Museum then studied the skull, using carbon dating which concluded that the skull belonged to a man who lived between AD 340 and 431, nearly 100 years after the death of Lucius in 254. So the skull in question never belonged to Lucius, who died around AD 254. The results also rule out that it may have belonged to the King Sigurd.