On 30 August 2008, the Libyan leader Muammar al-Gaddafi and Berlusconi signed a historic cooperation treaty in Benghazi. Under its terms, Italy will pay $5 billion to Libya as compensation for its former military occupation. In exchange, Libya will take measures to combat illegal immigration coming from its shores and boost investments in Italian companies. The treaty was ratified by Italy on 6 February 2009, and by Libya on 2 March, during a visit to Tripoli by Berlusconi. In June Gaddafi made his first visit to Rome, where he met Prime Minister Berlusconi, Italian President of the Republic Giorgio Napolitano and Senate's Speaker Renato Schifani. Gaddafi also took part in the G8 summit in L'Aquila in July as Chairman of the African Union. During the summit a warm handshake between US President Barack Obama and Muammar Gaddafi took place (the first time the Libyan leader has been greeted by a serving US president), then at summit's official dinner offered by President Giorgio Napolitano US and Libyan leaders upset the ceremony and sat by the Italian Prime Minister and G8 host, Silvio Berlusconi. (According to ceremony's orders Gaddafi should seat three places after Berlusconi)