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creer (Verb) "to believe"
12th cent. From Latin credere 'id.' From Proto-Italic *krezd-e/o- 'id.' From Proto-Indo-European *ḱred-dheh1- "to believe," but more literally "to place in one's heart." From *ḱērd- "heart" (see corazón).
Indo-European
Romance
Asturian creyer, Portuguese crer, Galician crer, Catalan creure, French croire, Italian credere, Aromanian creadiri, Romanian credere, Sardinian crèdere
Celtic
Old Irish creitid "to believe," Middle Welsh credu 'id.,' Middle Breton crediff 'id.,' Cornish cresy 'id.'
Indo-Iranian
Sanskrit śrad-dhā- "to believe"

An unusual semantic development of placing one's heart to signify concord of belief is mirrored in the Vulgar Latin development of acuerdo (from cor "heart") thousands of years later.

"The exact formal correspondence between Lat. crē-dō and Sanskrit śrad-dhā- is a guarantee of ancient heritage. Studies of the uses of śrad-dhā- in the Rig Veda show that the meaning of the word is “act of confidence (in a god), implying restitution (in the form of a divine favor accorded to the faithful).” The expression of the same complex notion, the IE *kred-, recurs in a secular sense in Latin crēdō ‘to entrust something with the certainty of recovering it’." ~ E. Benveniste, Indo-European Language and Society (1973)