<P> The term prime minister in its French form , premier ministre , is attested in 17th Century sources referring to Cardinal Richelieu after he was named to head the royal council in 1624 . The title was however informal and used alongside the equally informal principal ministre d'État ( `` chief minister of the state '' ) more as a job description . After 1661 , Louis XIV and his descendants refused to allow one of their ministers to be more important than the others , so the term was not in use . </P>
when was the term prime minister first used
1624