leaving the kingdom of Granada as the only Muslim
enclave in Christian Europe (see map 9.1).
Christendom was also on the advance in Sicily.
One problem with feudalism was that increases in the
population of the knightly class rapidly produced more
men trained in the profession of arms than could be
supported by existing fiefs. An expansion of their op-
portunities, like the Norman invasion of England, could
be seen as essential to social peace. Another group of
Norman adventurers, including the twelve sons of the
minor feudatory Tancred of Hauteville, had established
themselves in Italy by 1050. Pope Leo IX regarded
them as a threat. Later popes, realizing that the Nor-
mans could be useful allies in the investiture crisis,
supported one of Tancred’s sons, Robert Guiscard
(d. 1085), in his attempt to seize control of the Italian
south. Robert drove the Byzantine Greeks from Cal-
abria but left the conquest of Muslim Sicily to his
brother Roger (d. 1101). The process was completed in- Roger’s son, Roger II, used his inheritance to cre-
ate a powerful feudal kingdom on the Anglo-Norman
model. Its superior resources and his qualities as a gen-
eral enabled Roger to conquer all of southern Italy be-
fore his death in 1154.
164Chapter 9
Illustration 9.4
The Cathedral of Saint-Pierre,
Beauvais.Beauvais is in some ways an
extreme example of Gothic architectural
ambition. The choir was the tallest in
Europe until it collapsed in 1284.