Castile was the most powerful Christian kingdom of 10th-century Spain. Its chief city was Burgos. The kingdom was an important Christian political and military center until its conquest by the Moorish taifa of Nawar in 1035. Thereafter, Castile was a part of the Muslim world of Al-Andalus, but the population always remained heavily Christian. The King of St. John continued to use "King of Castile" as part of his royal title; the title is connected with the Crown of Asturias.