Another factor behind Italian town growth was the trans-Mediterranean trade of Pisa, Genoa, Venice, and Amalfi. By 1123, the Mediterranean was an Italian lake: the Egyptian navy was destroyed , and Levantine trade brought funds and self-sufficiency. Thus, the Crusades had a central role in changing the political balance of power in Europe itself, and helped new political as well as commercial technologies to survive--indeed, survive longer than those of surrounding states.
However, the towns' early governments failed, because when nobles entered the towns, so did feuds. In towns, noble alliances fought a lot, reducing the areas to urban battle zones. Towns could not maintain mutually friendly relations, as the post-1176 Lombard league collapse indicates, and this was too much urban strife to support further growth. At this stage, all attempts to secure inter- city amity failed when they were not under external threat, and only the coming of a second German specter, in the from of Frederick II, could bring them together, and then for a short period.
Having said this, what seems to emerge from Frederick II's measures in Sicily and Italy as compared to his policies in Germany is that he prioritized his southern possessions. In addition to their wealth, there are other reasons for this. Frederick II was a unique kind of Sicilian-cultured monarch. He grew up there, and imbibed totally its Muslim-Christian culture of political coexistence and cultural flowering. He spoke Arabic, and was a patron of the sciences coming west from the Middle East. He was also quite prepared to negotiate with Muslim leaders, as his 'Crusade' indicates. He has been called stupor mundi--the wonder of the world--by some who have admired his eclecticism, pragmatism, and openness to the cultures around him. The same conduct, though, earned him accusations of heresy and papal excommunication. In reference to his German and Italian policies, it seems that he was prepared to allow German princes as much autonomy as possible, as long as they recognized him as feudal sovereign and undertook certain responsibilities associated with this position. In Italy, though, he was looking for a much more centralized administration which he could use to assure him of direct control--politically as well as economically. Some historians have seen this as an encouraging foreshadowing of centralized Renaissance-period states, combined with a local delegation in the North. All of these initiatives--regarding Germany, the Pope, and Italy--were indeed too delicate to sustain. In an era of burgeoning Papal monarchy--when Innocent III could in effect be the one to assure the German king's own accession to the throne as his supposed lord, perhaps Frederick II combined too much, too early in Europe's political development.
The time of Frederick's death does, however, gives us a good vantage point on Europe. By 1250, the map of Europe was as follows: England up to Scotland was ruled by Henry III of the Norman-Angevin line. Most of Spain had been reconquered for the Christians. Portugal held the west coast, while Castile dominated the large central region. A small Navarre and a much larger Aragon were in the East, while a small Emirate of Grenada held on to the southern coast as the last Muslim state in Andalusia. France was under the unified feudal rule of St. Louis. The Holy Roman Empire of Frederick II comprised a Germany stretching from the North Sea to and including northern Italy, while the Papal States were wedged between German lands in the north and the south, in the form of Sicily. German princes had expanded into Bohemia, Austria, and had moved into Poland, converting the residents to Catholicism. Hungary had also Christianized, while to its east the looming Mongol Empire occupied much of Central Asia and Russia. They were stopped in their onslaught through the Middle East only by the Egyptian Mamluks outside of Palestine in 1260, at the Battle of Ayn Jalut. Latin Crusaders had usurped Byzantium's Thracian lands. The city-state of Venice was the prime commercial power in the region, followed by Amalfi, Pisa, and later Genoa. Finally, in 1261, the Byzantine Emperor of Nicaea Michael VIII Palaeologus was able to retake Constantinople, and held western Anatolia as well. Turkic tribes pushed west by the Mongol invasions had settled all of Anatolia up to the coastal areas and were thoroughly Islamicizing it. One of these tribal principalities to emerge in the next generation was that of Osman, the ancestor of the Ottoman Sultans.