There is no specific ‘start’ or ‘end’ date when it comes to feudalism in Germany or anywhere. It is best to say that feudalism in Europe occurred during the period known as the ‘High Middle Ages’. Classical feudalism occurred around the 10th century. The height of feudalism was during the 11th century and flourished in the 12th and 13th centuries. The decline started in the 13th century and continued until about the 15th century.
Feudalism had it’s strong and weak points. It’s strong points include things like a safer society, if compared to the late Roman empire and to Barbaric invasions. Feudalism divided people who lived to fight from quiet people, who did not want to be involved in wars. Wars were more diffused but seldom involving civilians. They were a problem between nobles. There was more social security; people were linked to their land or work. Somebody could not take land from somebody else without a good reason. The taxes were much lower than that of the late Roman Empire, and nothing if compared to today. The weak points of feudalism were that people were linked to their role; a noble would always have to be a noble, a knight would always be ready to fight, a peasant could no nothing more than to be a peasant.
Feudalism went away slowly in Germany. The rise of powerful monarchs in France, Spain, and England broke down local organization. Another disruptive force was the increase of communication, which broke down the isolated manor, assisted the rise of towns, and facilitated the emergence of the burgess class. This process was greatly accelerated in the 14th cent. and did much to destroy the feudal classifications of society. The system broke down gradually. It persisted in Germany until 1848. Many relics of feudalism still persist, and its influence remains on the institutions of Western Europe.