This article aspires to be a contribution to research on Latin translations of Maimonides, especially as it relates to the translation of Moreh Nevukhim named Dux neutrorum. Within this research we postulate a new hypothesis: the Roman origin of Dux neutrorum, and some investigative clues in Spanish catalogs covering historic Jewish translation area. Our intention is to show a possible relationship between the Hebrew manuscript of Al-Harizi and the mention of «cardinal romanus» present in one of the first incomplete Latin translation of Dux neutrorum, i.e., in the Liber de parabola. In this sense, we bracket the strongest historical hypotheses the 'Provence' and 'Sicilian' however not discarding their strong arguments.