Complex sentence: These fiefs thus gave rise to a complex relationship between landlord and tenant, involving reciprocal duties on both sides, for example the overlord in return for receiving his tenant's fealty or homage, took upon himself the duty to protect his tenant.
Split into simpler sentences: These fiefs thus gave rise to a complex relationship between landlord and tenant, involving duties on both sides. For example the overlord, in return for receiving his tenant's fealty or homage, took upon himself the duty to protect his tenant.