His attack on Thuringia ended in his defeat at Lucka in 1307, and, in the same year, the death of his son Rudolph weakened his position in eastern Europe.
Next the plains of eastern Europe were lost, then the AraloCaspian region, southern Russia and finally the valley of the Danube.
The conquest of Kazan was an epoch-making event in the history of eastern Europe.
It has profoundly affected and to a large extent subjugated all western Asia including India, all eastern and northern Africa as well as Spain, and all eastern Europe.
But in spite of this total political collapse, Arabic religion and literature are still one of the greatest forces working in the western half of Asia, in northern Africa and to some extent in eastern Europe.