The archbishop of Naples claimed that the dried blood of the city’s patron saint began to turn liquid in an ampoule on Saturday while Pope Francis was in the cathedral where the relic is stored.

During the mass in Naples on Saturday, he was given a vial of dried blood belonging to St. Gennaro, the city’s patron saint. The archbishop of Naples says when Francis kissed the glass, the blood half-liquified and the cardinal declared it a miracle.

The pope then joked that he and his congregation had to work harder since, quote, “the saint only loves us half-way.”

St. Gennaro was martyred in AD 305. The church’s followers believe that with enough prayer the preserved blood will liquify when it’s put on display during the three feast days celebrated each year.

Skeptics say the “miracle” is due to chemicals present in the ampoule that make the viscosity of the blood change when it is moved, as it was on Saturday when it was removed from the vault for the pope’s visit.

According to the Catholic Herald, Saturday was the first time the blood has liquified in the papal presence since 1848, when it did so in front of Pope Pius IX.