Complex sentence: Under the feudal structure that was arising in Japan, the samurai owed military service and loyalty to the emperor; the samurai in turn required loyalty and work from the peasants who rented land from them and served them.
Split into simpler sentences: Under the feudal structure that was arising in Japan, the samurai owed military service and loyalty to the emperor. The Samurai, in turn required loyalty and work from the peasants who rented land from them and served them.