Abū l-Walīd Marwān Ibn Janāḥ (fl. second quarter of the fifth/eleventh century), referred to as Rabbi Jonah or Rabi Marinus in Jewish sources, was a Jewish Andalusī physician and expert on logic, Hebrew grammar, and lexicography. Details about his life are scarce: he was born in Lucena or Córdoba in the last quarter of the fourth/tenth century, and died in Zaragoza after 429/1038 (Bos and Käs, 148). He studied Hebrew and Arabic language and literature in Lucena under Isaac b. Levi b. Mar Saul, Isaac b.