The French met the Byzantines: Odo of Deuil documented Greek treachery

Summary:
During the advance of Louis VII beyond Hungary into Byzantine lands, Odo convicted the Greeks of many breaches of faith, e.g. falsifying the exchange rate and letting food down in baskets rather than offering the promised market. It was unsure how far this was justified by German (and even French) attacks. Other Greek tricks he described included trying to send both Germans and French via the Dardanelles, giving a false guide, making some Frenchmen in the capital cross the straits with the Germans, attacking others (sometimes with godless Pechenegs), allying with the Turks, making false promises and insisting on heretical practices 
Dates:
1147 
Emperor Manuel I Komnenos (Manuel 1)
  • It was later remembered that his letter to Louis 101 Manuel claimed credit that was writing during a campaign against the infidel; the later peace with Mas'ud was therefore held against him (:) Odo of Deuil 54
Odo of Deuil, monk and historian (Odo 102)
  • During the advance of Louis 101 into Byzantine lands, Odo convicted the Greeks of many breaches of faith, e.g. falsifying the exchange rate and letting food down in baskets rather than offering the promised market; it was unsure how far this was justified by German (and even French) attacks (:) Odo of Deuil 40-42
  • Other Greek tricks he described included trying to send both Germans and French via the Dardanelles, giving a false guide, making some Frenchmen in the capital cross with the Germans, attacking others (sometimes with Pechenegs), allying with the Turks, making false promises and insisting on heretical practices (:) Odo of Deuil 46-60