Even though Sayyid Ajall was originally from Bukhara, not only Bukhara but Trans Oxiana was unknown to Iranians after it was separated from Iran following the Samanid fall and governed by a Turkish dynasty of Qatakhanid, which ruled over the territory until the Mogul invasion. For this reason, very little information is remained about Trans Oxiana in Persian historical sources. Sayyid Ajall was known to Iranians by his title and not by his real name Shams al-Din Omar. He was known through a historical book of Rashid ad-din Fazl Allah, who was roughly contemporary with Sayyid Ajall. As the Iranian ilkhanid gained independence from the Chinese Yuan dynasty, the information about this prominent Persian became increasingly scarce, so much so that when a descendant of Sayyid Ajall extended his genealogy to him in the 10th/16th centuries, probably very few people realized that he meant the same great Iranian official. This link was not reflected in later Persian historical sources. In modern times, because Iranian Studies and Chinese Studies have gone their own ways, and because Persian and Chinese scholars are not acquainted with each other's languages and cultural heritage, the opportunity for discovering this link was missed and, as far as our research shows, no one has apparently paid any attention to Sayyid Ajall's descendants in Iran.