At the first Council of Nicaea (325), there was a controversy over the expression of the relationship between Father and Son (God and Christ): one group wanted to use the word homoousion 'of the same substance', the other group said it should be homoiousion 'of like substance'. The first group prevailed, and homoousion (without the iota) was the word that was used in the formulation of the Nicene Creed.