June 29 is the Solemnity of Sts. Peter and Paul, the joint feast of the two apostles who founded the Church of Rome. According to the oldest tradition, both were martyred in the city under Nero, in the aftermath of the fire of 64 AD — Peter crucified upside down on the Vatican hill, and Paul beheaded on the Via Ostiense, as a Roman citizen. The feast is attested in the Depositio martyrum of 258, one of the oldest in the calendar.
The two basilicas of Rome — St. Peter's on the Vatican, and St. Paul Outside the Walls on the Via Ostiense — hold the apostles' tombs. On June 29 the pallium, the woolen band worn by metropolitan archbishops, is conferred on the new recipients by the Pope at St. Peter's. The pallium is made from the wool of two lambs blessed on the feast of St. Agnes (January 21) and woven by the Benedictine nuns of Santa Cecilia in Trastevere.
The feast was once kept with a great procession between the two basilicas — the Pope went in state from one to the other — and the custom survives in the station churches of the Roman calendar. From Rome, where the chain that bound Peter in the Mamertine prison is kept at San Pietro in Vincoli, to the churches of the worldwide communion, June 29 is the day of the Roman foundations.
