For his formal inauguration, Pope Benedict XVI adopted an earlier form of the pallium, from a period when it and the omophor were virtually identical. It is wider than the modern pallium although not as wide as the modern omophor, made of wool with black silk ends, and decorated with five red crosses, three of which are pierced with pins, symbolic of Christ's five wounds and the three nails, and it was worn crossed over the left shoulder. Only the Papal pallium was to take this distinctive form. Beginning with the Solemnity of Saints Peter and Paul (June 29, 2008) Benedict XVI reverted to a form similar to that worn by his recent predecessors, albeit in a larger and longer cut and with red crosses, therefore remaining distinct from pallia worn by metropolitans. This change, explained the Master of Pontifical Liturgical Celebrations Guido Marini, came about after recent studies on the history of the pallium, had shown that the oldest depiction of a pope wearing that type of pallium, that of Pope Innocent III at the Sacro Speco Cloister, seemed to be a deliberate archaism. Msgr. Marini also stated that Pope Benedict had had a series of annoying problems keeping it in place during liturgical celebrations. This pallium would later end up being worn by another pope when, while inspecting the damages caused by the 2009 L'Aquila earthquake Pope Benedict visited the badly stricken church of Santa Maria di Collemaggio. Here Pope Celestine V's remains had survived the earthquake, and after praying for a few minutes by his tomb, Benedict left the pallium on Celestine's glass casket. The last pope to abdicate willingly before Benedict XVI was Celestine V in 1294.