Not To Be Confused With
This is “confession” as a statement of belief (the Augsburg Confession), not “confession” as the admission of sin in the sacrament of penance.
Confessions arose especially in the Reformation, as churches set out their teaching in detail: the Augsburg Confession (Lutheran), the Westminster Confession (Reformed), the Belgic Confession, the 1689 Baptist Confession. They define a tradition's stance where creeds stay general.