In 313 ce, constantine the great issued the edict of milan. what effect did this law have

The Edict of Milan is an agreement concluded in February 313 between Constantine, Emperor of the Western Roman Empire and Licinius, Emperor of the Byzantine Empire. The agreement ensured Christianity's equality with other religions of the Roman Empire, with the addition that all ecclesiastical property previously confiscated should be restored to the church.  

This edict continued the Edict of Tolerance of Galerius of 311, which allowed Christians to practice their religion. The Edict of Milan meant that all forms of persecution based on religion were then stopped. In 380, under Emperor Theodosius, Christianity became state religion in the Roman Empire.

the qing dynasty placed strict limits on foreign merchants' ability to trade in china.