Where did the term "cardinal sin" originate?

A cardinal sin is the same as a deadly sin, a product of early Christian monasticism and Saint Gregory the Great of the late sixth century. The seven deadly sins are vainglory (pride), covetousness, lust, envy, gluttony, anger, and sloth. They were classified as “deadly” not only because they were serious moral offenses but also because they frequently resulted in the commission of other sins. These days, “cardinal sin” is popularly used for any major sin.