Claim: Süleyman Çelebi fought in the Battle of Nigbolu and the Battle of Ankara, the former of which is also known as the Crusade of Nicopolis.
Evidence: It is often referred to as the Crusade of Nicopolis as it was one of the last large-scale Crusades of the Middle Ages, together with the Crusade of Varna in 1443–1444. He fought both in the Battle of Niğbolu (1396) against the Crusaders and the Battle of Ankara (1402) against Temurlane.