What was a key contribution from justinian's reign ?

During his reign he made efforts to regain the lost provinces of the western Roman Empire. He also changed Roman law. And he made several architectural achievements. 

The fifteenth amendment did not give women the right to vote; it prevented individuals from being prohibited to vote based on race, color, or previous condition or servitude, but not gender. Women had to wait until 1920 for the 19th amendment to be passed to get the right to vote.