William I of Sicily William I ( 1131 – May 7 , 1166 ) , called the Bad or the Wicked , was the second King of Sicily , ruling from his father ' s death in 1154 to his own in 1166 . He was the fourth son of Roger II and Elvira of Castile . William ' s title " the Bad " seems little merited and expresses the bias of the historian Hugo Falcandus and the baronial class against the king and the official class by whom he was guided . Early life . William was the son of King Roger II of Sicily , grandson of Roger I of Sicily and great - grandson of Tancred of Hauteville . He grew up with little expectation of ruling . The deaths of his three older brothers Roger , Tancred , and Alfonso between 1138 and 1148 changed matters , though when his father died William was still not well - prepared to take his place . Kingship . On assuming power , William kept the administration which had guided his father ' s rule for his final years . Only the Englishman Thomas Brun was removed , and the chancellor Maio of Bari was promoted . The real power in the kingdom was at first exercised by Maio , a man of low birth , whose title " ammiratus ammiratorum " was the highest in the realm . Maio continued Roger ' s policy of excluding the nobles from the administration , and sought also to curtail the liberties of the towns . The barons , always chafing against the royal power , were encouraged to revolt by Pope Adrian IV , whose recognition William had not yet sought , by the Byzantine Emperor Manuel I Comnenus , and by the Holy Roman Emperor Frederick I . At the end of 1155 , Greek troops recovered Bari , Trani , Giovinazzo , Andria , Taranto and began to besiege Brindisi . William and his army landed on the peninsula and destroyed the Greek fleet ( 4 ships ) and army at Brindisi on May 28 , 1156 and recovered Bari . Adrian came to terms at Benevento on June 18 , 1156 where he and William signed the Treaty of Benevento , abandoning the rebels and confirming William as king . During the summer of 1157 , he sent a fleet of 164 ships carrying 10 , 000 men to sack Euboea and Almira . In 1158 William made peace with the Greeks . These diplomatic successes were probably due to Maio ; on the other hand , the African dominions were lost to the Almohad s , and it is possible that he advised their abandonment in face of the dangers threatening the kingdom from the north . In 1156 , a revolt began in Sfax and quickly spread and nothing was done to put it down . In 1159 , the admiral Peter led a raiding expedition against the Saracen - held Balearic Islands with 160 ships . He tried to relieve besieged Mahdia with the same fleet , but turned around just after engaging in battle . Peter did not fall out of favour , but no further assistance was sent to the Christians holding out in Mahdia and the city surrendered on 11 January 1160 , ending the " African empire . " The policy of Maio led to a general conspiracy , and in November 1160 Maio was murdered in Palermo by Matthew Bonello , leader of the Sicilian nobles . The barons , however , had long been plotting to overthrow the king . Desiring a weak power on the throne , they had been eyeing the king ' s eldest son , Roger , Duke of Apulia , as a possible replacement for his father . After the assassination of Maio , the royal palace was stormed by two of the king ' s own relatives : his illegitimate half - brother Simon , whom he had dispossessed of Taranto early in his reign and his bastard nephew Tancred , the count of Lecce . The king was captured along with his whole family , his life being barely spared by one Richard of Mandra . Roger was then paraded through the streets and it was announced that he would be crowned in the cathedral three days thence . For a while the king remained in the hands of the conspirators who purposed murdering or just deposing him , but the people and the army rallied round him ; he recovered power , crushed the Sicilian rebels , had Bonello blinded , and in a short campaign reduced the rest of the " Regno " , avenging the rebel burning of Butera . During the initial assault on the palace , to release the captive king , the king ' s son Roger was killed by a wayward arrow ( though the historian Falcandus , seemingly ever - ready to impugn the royal character , has the king kicking his " faithless " son dead ) . Later years . Thus freed from feudal revolts , William confided the government to men trained in Maio ' s school , creating a triumvirate : the grand protonotary , Matthew of Ajello ; Count Sylvester of Marsico , who had inherited Maio ' s property ; and the Bishop Palmer of Syracuse , elect , but not consecrated . His latter years were peaceful ; he became the champion of the true pope against the holy roman emperor , and Alexander III was installed in the Lateran Palace in November 1165 by a guard of Normans . William died on May 7 , 1166 and was interred in Palermo Cathedral , although he was later moved to Monreale Cathedral by his son and heir William II of Sicily when that building was completed . By his wife , Margaret of Navarre , daughter of García Ramírez of Navarre , he had four sons :