The author's aim is to 'tell the remarkable story of the Fourth Crusade--an episode coloured by brutality and determination; depravity and avarice, political intrigue and religious zeal' and to explain 'why the crusade followed the course it did' by looking at underlying causes which included frequent conflict between Western Europe and the Byzantine Empire, lack of money (which the sack of Constantinople could provide) or the murder of the Emperor, Alexius IV
. Whilst the author does not seek to justify he does try to explain why things turned out as they did.
In the interim, their hopes of receiving the support promised by the Prince (now Emperor Alexius IV) had evaporated.
Until the murder of Alexius IV their hopes might have been realised, but after this they were trapped, Ironically, in the long run, the need to support the new Latin Empire of Constantinople against Byzantine counter-attacks proved a drain on the crusading resources of the West, and by 1261 Constantinople was again in Greek hands.
There is the ill-fated popinjay, Alexius, Greek claimant to the Byzantine throne, who promised more than he could deliver, as events demonstrated after he was raised to the purple as Alexius IV
. And there are a score of other figures--dashing knights, stunningly beautiful ladies, unscrupulous behind-the-throne manipulators, abject cowards, warriors with their genuine but simple faith, savage Bulgarian hordes, and on and on.
Or were some of the peripheral players, such as Alexius IV
or Philip of Swabia, responsible?