The Tombs of Osman and Orhan sit side-by-side on the top of a hill in Tophane Park in the city of Bursa. Osman Gazi, also known as Osman I, was the founder and first sultan of the Ottoman Empire. His son, Orhan, conquered Bursa, which became the capital of the Ottoman Empire for 130 years.
Unfortunately, the original tombs were completely destroyed by an earthquake that rocked Bursa in 1855 and the structures standing today were built in 1868 by Sultan Abdulaziz in the Ottoman baroque style. The Tomb of Osman is the more ornate of the two tombs and sits on the ruins of the chapel of the Byzantine monastery St. Elie. The Tomb of Orhan was constructed on the floor mosaics of the St. Elie monastery and includes 14 coffins, including those of Orhan, his wife and children.
The Tombs of Osman and Orhan are located in Tophane area of Bursa and are open daily from dawn to dusk. From Ulu Cami, follow Orhan Gaz Caddesi uphill to the tombs.
The city of Bursa is about a four hour bus ride from Istanbul, with buses leaving the main bus station frequently throughout the day. However, you may find it more convenient to join a day tour from Istanbul that will allow you to see many of the main sights of Bursa, including the Tombs of Osman and Orhan.