Yöngyulü Tülan-Qağan (Tunga-Turan, Tulan-Khan, 都蘭可汗, 雍虞閭) was the son of Ishbara an the seventh qaghan of the Göktürk empire. He married his father's wife, Northern Zhou's Princess Qianjin, now known under the Sui Dynasty title Princess Dayi. Her new name was given to her by the Sui Emperor Wendi in order to create a marriage alliance with the Turks. Secretly, she plotted with Dulan-qaghan's rival, Tuli to to attack the Sui Empire when her husband refused. This plot was exposed by Chang sun-sheng, a spy of the Sui Empire.