1st Council of Nicaea 325AD → Nicene Creed
Synod in Milan 390AD → Apostles’ Creed
Part of the reasons for the convening of the many Synods in Milan (340-390s) were the Jovinian Heresy (abstinence and sex in the framework of pleasure related heresy) was spreading, condemnation of Bishop Athanasius of Alexandria, and the Filioque Controvery (issue of if the Holy Spirit proceeds from the Father and the Son, which was doubted in spreading Eastern Orthodoxy.
As a result, around 390AD, Pope Siricius wrote in an encyclical the need for an official layed our foundational creed, he coined the term ‘Apostles’ Creed’. I took a class on the historical and foundational basis for Christianity, Judaism, and Islam and these councils and others were covered extensively