Herbert Franke pointed out that the sinicization of the Mongols rulers was never fully achieved, after a long period of potential acculturation and gradual sinicization, and a number of turning pointes He has distinguished several stages in the transition from steppe rulership to (never fully realized) Chinese emperorship and back to the steppes.
1. The old-Mongol period up to Chinggis Khan's accession in 1206;
2. The conquest of Peking and parts of Northern China, marked by the years 1215 (conquest of Peking) and 1234 (extinction of the Jin state).
3. the rule of Khubilai Khan (1260-1294, where several sub-stages could be determined);
4. the late reigns of the MongoL emperors (1294-1368);
5. the influence on the Mongols of their rule over China after their expulsion in 1368. The gradually and never fully achieved sinicization of the Mongol rulers was, of course, the chief element underlying the methods and symbol of their legislation in the eyes of their Chinese subjects.