may 1, 787 - Second Council of Nicaea

Description:

to restore the use and veneration of icons (or, holy images),[1] which had been suppressed by imperial edict inside the Byzantine Empire during the reign of Leo III (717–741). His son, Constantine V (741–775), had held the Council of Hieria to make the suppression official.

https://en.wikipedia.org/wiki/Second_Council_of_Nicaea