Which of the following was the most significant legacy ofthe sixth-century Byzantine emperor Justinian I?

While Justinian faced financial challenges, his administration did not focus primarily on resolving debts. Instead, his reign is marked by ambitious military campaigns and legal reforms. The handling of debts was more a matter of governance rather than a defining legacy, overshadowed by his monumental legal achievements.

Justinian did not subdue the Parthian Empire; rather, it was the Sassanian Empire that was a contemporary power in the east. His military efforts were largely directed towards the reconquest of former Roman territories in the west, such as Italy and North Africa. Thus, this choice does not accurately reflect the core accomplishments of his reign.

While Justinian did address issues surrounding iconoclasm, his approach did not fully resolve the controversy. The debate over religious images persisted long after his reign, indicating that this issue was not a definitive aspect of his legacy as much as his legal reforms were.