A woman vaulted a barrier inside St. Peter's Basilica and knocked Pope Benedict XVI to the floor as he arrived to celebrate Mass marking the beginning of Christmas. The 82-year-old pontiff was uninjured and was able to deliver his Christmas Eve homily. Vatican officials said the woman appeared to be mentally unstable and was arrested by Vatican police. She was identified as Susanna Maiolo, 25, a Swiss-Italian national. In his homily, Benedict urged the world to “wake up” from selfishness and petty affairs. At the Vatican, witness video obtained by the AP showed Maiolo dressed in a red hooded sweat shirt jumping over the wooden barriers that cordoned off the basilica's main aisle and rushing toward the pope before being swarmed by bodyguards. She grabbed the pope's vestments as she was taken down, with Benedict seemingly falling on top of her. The commotion happened as the pope's procession was making its way toward the main altar and shocked gasps rang out through the public that packed the basilica. The procession came to a halt and security rushed to the spot. Vatican spokesman the Rev. Ciro Benedettini said the woman also knocked down French Cardinal Roger Etchegaray, who was taken to a hospital for a checkup. “During the procession an unstable person jumped a barrier and knocked down the Pope,” Benedettini told the AP by telephone. “(The pope) quickly got up and continued the procession.”