By David Willey
BBC News, Rome
The former president of Iran, Mohammad Khatami, has been received in audience by Pope Benedict XVI in Rome.
Papal envoys have been working hard to repair damaged relations
He is the most senior figure in the Muslim world to visit the Vatican since the Pope's much-criticised remarks last year linking Islam with violence.
Vatican diplomats have been working overtime for months to try to patch up relations with the Muslim world.
The Pope's words last year, made during a lecture in Germany, were interpreted as offensive by some Islamic states.
The Pope insisted his words had been taken out of context and that he meant no offence to the Muslim religion.
This visit to the Vatican by the former president of Iran, postponed from last year, marks the beginning of a new series of public and private initiatives taken by the Vatican to try to improve understanding between Christians and Muslims.
Iran has maintained diplomatic relations with the Holy See for more than 50 years, including during the turbulent years of the Islamic revolution.
The Iranians see the papacy as a powerful influence, and a possible bulwark against the threatened use of force by the US during the current international crisis over Iran's nuclear ambitions.
After meeting the Pope, Mr Khatami will speak at a two-day seminar at the Gregorian University - the pontifical university - on peace in Islam and the Christian world.
He will also have meetings with the Italian Prime Minister Romano Prodi and the country's foreign minister before travelling to Milan and other parts of Italy for more meetings at other Italian universities.
Next week there will be another unprecedented move by the Vatican: a three-week-long university seminar for diplomats from Iran, Iraq, Saudi Arabia and over a dozen more other predominantly Muslim countries.
They will discuss how the Vatican works behind the scenes to mediate between states, cultures, religions and peoples.