Robert is believed to have been educated at the Cathedral School of Paris. In 1134 he travelled from France to the East for four years with his fellow student and friend Herman of Carinthia (also known as Herman Dalmatin). They visited the Byzantine Empire, the Crusader States in Palestine and Damascus. Both men were to become famous as translators from the Arabic. By 1141 Robert had moved to Spain where the division of the country between Muslim and Christian rulers made it a natural base for translators. Some sources identify him with Robert of Chester (Latin: Robertus Castrensis), who was also active in Spain as a translator in the 1140s.
Although he received support from the Church—he became Archdeacon of Pamplona in 1143—Robert's preference was for translating scientific rather than theological works. He is known to have studied Euclid and to have translated the work of Al Battani and Avicenna, and it seems that he would not have made the translation for which he is famous, that of the Qur'an, without the encouragement of the French Abbot Peter the Venerable, who wished to have access to Islamic texts. In 1142 Robert and other scholars met with Peter the Venerable, who was visiting Spain, and Robert set to work translating the Qur'an into Latin. The translation was done by 1143; entitled Lex Mahumet pseudoprophete, it was the first translation of the book into a European language and remained the standard well into the sixteenth century. The last record we have of Robert's career is that he became a canon of Tudela in 1157.