Old Occitan (Modern Occitan: occitan ancian, Catalan:occità antic), also called Old Provençal, was the earliest form of the Occitano-Romance languages, as attested in writings dating from the eighth through the fourteenth centuries. Old Occitan generally includes Early and Old Occitan. Middle Occitan is sometimes included in Old Occitan, sometimes in Modern Occitan. As the term occitanus appeared around the year 1300, Old Occitan is referred to as "Romance" (Occitan: romans) or "Provençal" (Occitan: proensals) in medieval texts.
The Old Catalan language diverged from Old Occitan between the eleventh and fourteenth centuries. Early texts in the Catalan dialect are the Homilies d'Organyà, Cançó de Santa Fe and the Greuges de Guitard Isarn. It never underwent the shift from /u/ to /y/, nor the shift from /o/ to /u/ (except in unstressed syllables in some dialects), so it had diverged phonologically before those changes affected Old Occitan.