of the servile classes, which were delayed in achieving emancipation in these regions much longer than in other parts of Spain. [Sidenote: Coming of the monks of Cluny.] [Sidenote: Backwardness of Pyrenean Spain.] The most important religious incident of the period was the entry of the monks of Cluny into Spain. This order had taken it upon itself to combat simony (the sale of church office) and offences against the ecclesiastical law of celibacy (requiring that men who had taken holy orders should not marry), both of which practices were than very prevalent in Christendom, and to bring about a complete and effective submission of distant churches to the bishop of Rome. These monks came into Spain by way of Navarre in the reign of Sancho the Great, and by 1033 they were already in Castile. Aside from their immediate objects they produced two other important effects: they reinforced the French ideas which had preceded them; and they accelerated the reconquest as a result of the influence which they acquired, employing it to urge on the kings in wars against the Moslems. In economic institutions, general culture, and the fine arts the north centre and northeast were very backward, like the northwest. It is noteworthy, however, that by the ninth century the Catalans were already beginning to engage in trade in the Mediterranean. DEVELOPMENT TOWARD NATIONAL UNITY, 910-1492 [Illustration: Spain in 910] [Illustration: Spain in 1130] [Illustration: Spain in 1037] [Illustration: Spain 1212-1492] CHAPTER VII ERA OF THE SPANISH CRUSADES, 1031-1276 [Sidenote: General characteristics of the era.]