ðə lˈaɪbɹi kˌæɹəlˈiːni"tʃˈɑːɹlz bˈʊks", mˈoːɹ kɚɹˈɛktli ˈoʊpəs kˈæɹɑːli ɹˈiːdʒɪs kˈɑːntɹə sɪnˈɑːdəm"ðə wˈɜːk ʌv kˈɪŋ tʃˈɑːɹlz ɐɡˈɛnst ðə sˈɪnɑːd", ɪz ɐ wˈɜːk ɪn fˈoːɹ bˈʊks kəmpˈoʊzd ɔnðə kəmˈænd ʌv tʃˈɑːɹlɪmˌæɡni ɪnðə mˈɪd sˈɛvənhˈʌndɹɪd nˈaɪnti z tə ɹᵻfjˈuːt ðə kəŋklˈuːʒənz ʌvðə bˈɪzɐntˌiːn sˈɛkənd kˈaʊnsəl ʌv nɪkˈiə sˈɛvənhˈʌndɹɪd ˈeɪɾi sˈɛvən, pɚtˈɪkjʊlɚli æz ɹᵻɡˈɑːɹdz ðə mˈæɾɚɹ ʌv sˈeɪkɹɪd ˈɪmɪdʒᵻz.
The Libri Carolini ("Charles' books"), more correctly Opus Caroli regis contra synodum ("The work of King Charles against the Synod"), is a work in four books composed on the command of Charlemagne in the mid 790s to refute the conclusions of the Byzantine Second Council of Nicaea (787), particularly as regards the matter of sacred images.