Beginning in August 1980, Ağca, under the alias of Vilperi, began criss-crossing the Mediterranean region, changing passports and identities, perhaps to hide his point of origin in Sofia, Bulgaria.
He entered Rome on 10 May 1981, coming by train from Milan.
According to Ağca's later testimony, he met with three accomplices in Rome, one a fellow Turk and two Bulgarians, with the operation being commanded by Zilo Vassilev, the Bulgarian military attaché in Italy.
He said that he was assigned this mission by Turkish mafioso Bekir Çelenk in Bulgaria.
According to Ağca, the plan was for him and the back-up gunman Oral Çelik to open fire on the pope in St. Peter's Square and escape to the Bulgarian embassy under the cover of the panic generated by a small explosion.

On 13 May, they sat in the square, writing postcards waiting for the Pope to arrive.
When the Pope passed through an adoring and excited crowd of supporters, Ağca fired four shots at 17:17 with a 9mm Browning Hi-Power semi-automatic pistol, and critically wounded him.
He fled the scene as the crowd was in shock and disposed of the pistol by throwing it under a truck, but he was grabbed by Vatican security chief Camillo Cibin, a nun, and several spectators who prevented him from firing more shots or escaping, and he was arrested.
All four bullets hit John Paul II; two of them lodged in his lower intestine while the other two hit his left index finger and right arm and also injured two bystanders: Ann Odre, of Buffalo, New York, was struck in the chest, and Rose Hall was slightly wounded in the arm.
The Pope was immediately rushed to the hospital while the authorities combed the site for evidence.
Çelik panicked and fled without setting off his bomb or opening fire.
Beginning in August 1980, Ağca, under the alias of Vilperi, began criss-crossing the Mediterranean region, changing passports and identities, perhaps to hide his point of origin in Sofia, Bulgaria. He entered Rome on 10 May 1981, coming by train from Milan. According to Ağca's later testimony, he met with three accomplices in Rome, one a fellow Turk and two Bulgarians, with the operation being commanded by Zilo Vassilev, the Bulgarian military attaché in Italy. He said that he was assigned this mission by Turkish mafioso Bekir Çelenk in Bulgaria. According to Ağca, the plan was for him and the back-up gunman Oral Çelik to open fire on the pope in St. Peter's Square and escape to the Bulgarian embassy under the cover of the panic generated by a small explosion.
On 13 May, they sat in the square, writing postcards waiting for the Pope to arrive. When the Pope passed through an adoring and excited crowd of supporters, Ağca fired four shots at 17:17 with a 9mm Browning Hi-Power semi-automatic pistol, and critically wounded him. He fled the scene as the crowd was in shock and disposed of the pistol by throwing it under a truck, but he was grabbed by Vatican security chief Camillo Cibin, a nun, and several spectators who prevented him from firing more shots or escaping, and he was arrested. All four bullets hit John Paul II; two of them lodged in his lower intestine while the other two hit his left index finger and right arm and also injured two bystanders: Ann Odre, of Buffalo, New York, was struck in the chest, and Rose Hall was slightly wounded in the arm. The Pope was immediately rushed to the hospital while the authorities combed the site for evidence. Çelik panicked and fled without setting off his bomb or opening fire.
Attempted assassination of Pope John Paul II