On Confession to a Priest

QUESTION: When did the people first confess their sins to a priest?

ANSWER: In the fourth century the bishops began to give absolution without confession in public, but privately. But it did not become imperative as a sacrament, once a year, till the Fourth Lateran Council in A. D. 1215. Then it became an indispensable duty laid upon every one from the Emperor to the peasant, to open the whole heart to the priesthood.

—  Steele's Answers p. 176.