Why did justinian's reconquest of the western roman empire fail? he was forced to withdraw his army to meet the growing islamic threat. western christians no longer felt kinship with eastern christians. he codified roman law, which made permanent conquest impossible. the costs of conquering and defending a western empire were too great?

The answer is D) The cost of conquering and defending a Western empire were too great.

Justinian tried to reconquer the former Roman Empire territories. He was very successful at it first. The Byzantine armies conquered the North Africa and Sardinia.

He was eager to get more victories and sent his army to Italy. But the Ostrogoths were strong too and fighting continued for years. Even Franks joined the fight and won a few battles.

But the overall effects were devastating. The population of Italy reduced significantly, the armies perished from fighting, and even Justinian captured Rome at some point, his armies could not defend the city against invaders. It was just too costly, and hard to defend.