Curiously, modern historians have largely overlooked this critical aspect of Mediterranean history. There are no major works whatsoever on Norman sea power. The only extant study devoted to the subject is a 104-page booklet produced in German by Willy Cohn a century ago. While Cohn deserves credit for recognizing the significance of the study and identifying valuable sources, his work unfortunately is flawed by almost all accounts. It is basically an amalgamation of narratives on Norman naval engagements excerpted from the Norman chronicles and accompanied by superficial analysis. He devotes little attention to ship types, crew composition, recruitment, naval organization or tactics; and there is almost no mention at all of the impact on the medieval Mediterranean.

Aside from these glaring deficiencies, Cohn's approach was tainted by a number of misconceptions. For instance, he makes the unwarranted assumption that the early Norman conquerors, specifically Robert and Roger de Hauteville, designed and built their own vessels from the very beginning. There is no evidence of this. In fact, the Norman chronicler William of Apulia was probably quite right when he asserted, ‘The Norman race had up to this point known nothing of naval warfare.’ Cohn also made the peculiar decision to concentrate only on the Sicilian fleets of Roger I and Roger II, based upon the unsubstantiated notion that the fleets of Robert Guiscard and Roger were entirely separate. The premise of separate fleets was invalid. Roger was Robert's vassal.