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In page Roger II of Sicily:

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The popes had long been suspicious of the growth of Norman power in southern Italy, and at Capua in December, the pope preached a crusade against Roger, setting Robert II of Capua and Ranulf II of Alife (his own brother-in-law) against him. After this coalition failed, in August 1128 Honorius invested Roger at Benevento as Duke of Apulia.[1] The baronial resistance, backed by Naples, Bari, Salerno, and other cities whose aim was civic freedom, gave way. In September 1129 Roger was generally recognized as duke of Apulia by Sergius VII of Naples, Robert of Capua, and the rest. He began at once to enforce order in the duchy, where ducal power had long been fading.