Leaders at the summit of the Organisation of Islamic Cooperation (OIC) in Istanbul include King Salman of Sunni power Saudi Arabia and President Hassan Rouhani of Shiite Iran whose countries are pitted on opposing sides in Syria and Yemen.
But with Turkey seeing the summit as a chance to shore up its prestige in the Islamic world, Erdogan has made it his mission at the meeting to bring the world's 1.7 billion Muslims closer together.
"At this summit, our biggest expectation is for Islamic countries throughout the world to give a message of unity and togetherness to all Muslims," Erdogan told leaders beneath the dome of the vast Muayede Salon, the ceremonial hall where the Sultan would receive visitors.
"Our aim is to give the whole Islamic family hope in the future. God willing, with this summit, a new era will begin for all of us."
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Erdogan, whose country now holds the chairmanship of the OIC for the next two years, was due to chair the last sessions of the summit Friday before holding a news conference.
The meeting has been marked by signs of a strong emerging alliance between Turkey and fellow Sunni Muslim power Saudi Arabia, whose foreign ministers Thursday signed a memorandum on creating a bilateral cooperation council.
Both countries, along with the tiny but gas-rich Gulf state of Qatar, back rebels fighting the regime of President Bashar al-Assad in Syria.
Analysts have warned Turkey needs to tread carefully in its alliance with Saudi Arabia, so it is not seen as a sectarian union aimed at Iran.
In a sign of Ankara's desire to maintain a delicate balance, Rouhani is due to begin a bilateral visit to Turkey immediately after the summit.