In the case-book of the al-Andalus jurist Ibn Sahl (1022-1093), appear four affairs relating to the sale of Equids : they concern inherent defects which put into question the validity of the transaction and where the veterinary was called in. An interdisciplinary approach can suggest some reflections on these cases : the documents allow a nuanced picture of equine breeding in al-Andalus, through a local industry of she-mules breeding which is very different from that of Majorca, through local animals in a poor sanitary state inferior to the splendid mounts evoked in the chronicles or in the " chivalry " treatises. These cases equally allow us to see the veterinary in action, a professional whose mastery and practise of hippologic knowledge as evoked in the hippiatric treatises, are noted. Finally, these cases hint at a proposed solution in the matter of protection of the buyer faced with hidden flaws : a very long - even an unlimited- period to contest the sale.
Hidden flaws, equids, Al-Andalus, veterinary, Ibn Sahl.