In the twelfth century, the Norman Kingdom of Sicily rose to rival the great maritime republics of the Italian peninsula for dominance of the Mediterranean. But it did so in a manner quite dissimilar to that of Genoa, Pisa, or Venice. The Norman realm's unique approach to the development and employment of naval power has much to do with how the kingdom was created and the mindset of its creators. Those who founded it were, at their core, mounted men-at-arms and conquerors. The Normans who migrated into the Mezzogiorno (southern Italy and Sicily) in the eleventh century were indigent knights – soldiers of fortune – offering their swords for rent in return for plunder. When their activities inevitably evolved from mercenary enterprise and organised brigandage to overt conquest, the Normans adopted sea power as a pragmatic means for effecting the seizure of Sicily – the island that would ultimately become the core of their kingdom. Their first ships were commandeered vessels of commerce that they used to literally ferry their armies across the Strait of Messina. Once the conquest was completed, they deployed their burgeoning fleets almost entirely to defend their acquisition and aggrandise its hegemony to include the whole of the central Mediterranean.

In comparison, the north Italian maritime republics had adopted an altogether different modus operandi for employing their naval capability. And they did so to achieve vastly contrasting objectives, also rooted in their origins. They were born as mercantile communities wedded to the sea. While their citizens may have begun as freebooters and coastal traders, these innate seafarers quickly embraced maritime commerce on a grand scale as their principal occupation. And the nature of that commerce was overwhelmingly the transportation of desired goods from their sources to markets where they could be sold at a significant profit or exchanged for products in demand elsewhere in the Mediterranean world. As a consequence, the primary purpose of their fleets was to expand their markets and extend their trade routes. Routes to the Orient became particularly lucrative, especially after the onset of the crusading movement in the late eleventh century.