The Council of Nicaea was a church council held in the year 325AD, The council came together to come to a concensus on official church practices. The results of the council were as follows:
The creation of the Nicaean Creed solidified the holy trinity (father, son and holy spirit) as opposed to Jesus being subordinate to god as a mortal (could commit sin)
The Council of Nicaea also proposed a variety of adminstrative reforms, such as strict internal church hierarchy, established rules for moral conduct of the clergy, and outlined uniform punishments for breaching rules (also known as heresy).