Intermarriage between Visigoths and Hispano-Romans was prohibited, though in practice it could not be entirely prevented and was eventually legalised by Liuvigild. The Spanish-Gothic scholars such as Braulio of Zaragoza and Isidore of Seville played an important role in keeping the classical Greek and Roman culture. Isidore was one of the most influential clerics and philosophers in the Middle Ages in Europe, and his theories were also vital to the conversion of the Visigothic Kingdom from an Arian domain to a Catholic one in the Councils of Toledo. Isidore created the first western encyclopedia which had a huge impact during the Middle Ages.