Scott’s account, as already remarked upon, is clearly influenced by The Alexiad. Here is Anna Komnene’s assessment of the first crusaders:
[The Emperor] had no time to relax before he heard a rumour that countless Frankish armies were approaching. He dreaded their arrival, knowing as he did their uncontrollable passion, their erratic character and their unpredictability, not to mention the other characteristics of the Kelt, with their inevitable consequences: their greed for money, for example, which always led them, it seemed to break their own agreements without scruple. 
The simpler folk [participating in the Crusade] were led by a genuine desire to worship at Our Lord’s tomb and visit the holy places, but the more villainous characters, in particular Bohemond and his like, had an ulterior motive, for they hoped on their journey to seize the capital itself, looking upon its capture as a natural consequence of the expedition.
Bohemond disturbed the morale of many nobler men because he still cherished an old grudge against the emperor. 
Peter [the Hermit] had in the beginning undertaken his great journey to worship at the Holy Sepulchre [in Jerusalem], but the other counts, and in particular Bohemond, were nursing an old grudge against the emperor and were looking for a good opportunity to avenge the glorious victory which the emperor had won at Larissa against Bohemond. They were all of one mind and in order to fulfill their dream of taking Constantinople, they adopted a common policy, which I have often referred to before: to all appearances they were on pilgrimage to Jerusalem; in reality they planned to dethrone the emperor and sieze the capital. 
Let us compare the above to Scott: “In his [Emperor’s] first sentences, he treated of the audacity and unheard of boldness of the millions of Franks, who under, the pretence of wresting Palestine from the Infidels, had ventured to invade the sacred territories of the empire”. 
Anna Komnene describes in great detail of the raids on the Byzantine Empire by the Patzinaks (or Pechenegs), steppe nomads who had established themselves on Byzantium’s Danube frontier, and were regularly raiding Imperial territory by the 1070s. She also devotes much attention to the relations with the Turks, campaigns against the Cumans, and Scythians [for example, The Alexiad, Book, VIII] throughout Alexius’ reign.
Inspired by her, Scott gives a very vivid and accurate picture of the problems besetting the Emperor on all sides, and tells us of his various alliances by which difficult juggling act he was able to play one side off another:
In different parts of his territory, different enemies arose, who waged successful or dubious war against the Emperor; and, of the numerous nations with whom he was engaged in hostilities, whether the Franks from the west, the Turks advancing from the east, the Cumans and Scythians pouring their barbarous numbers and unceasing storm of arrows from the north, and the Saracens, or the tribes into which they were divided, pressing from the south, there was not one for whom the Grecian empire did not spread a tempting repast. Each of these various enemies had their own particular habits of war, and a way of manoeuvring in battle peculiar to themselves. But the Roman, as the unfortunate subject of the Greek empire was still called, was by far the weakest, the most ignorant, and most timid, who could be dragged into the field; and the Emperor was happy in his own good luck, when he found it possible to conduct a defensive war on a counterbalancing principle, making use of the Scythian to repel the Turk, or of both these savage people to drive back the fieryfooted Frank, whom Peter the Hermit had, in the time of Alexius, waked to double fury, by the powerful influence of the crusades. 
Anna talks of the many heresies that Alexius felt obliged to extirpate in order to guard the purity of the Church: the heresy of John Italos [pp146-52]; Paulicianism [155-6, 424]; of Neilos [260-61]; of Blakhernites ; Bogomilism [424, 455-63]; Manichaeanism [424-30].
Here Scott summarizes elegantly, and at the same time, subtly pleads for religious toleration for the heretics:
[Alexius] took a deep interest in all matters respecting the church, where heresy. Which the Emperor held, or affected to hold, in great horror, appeared to him to lurk.Nor do we discover in his treatment of the Manichaeans or Paulicians that pity for their speculative errors which modern times might think had been well purchased by the extent of the temporal services of these unfortunate sectaries. Alexius knew no indulgence for those who misinterpreted the mysteries of the church, or of its doctrines; and the duty of defending religion against schismatics was, in his opinion, as peremptorily demanded from him, as that of protecting the empire against the numberless tribes of barbarians who were encroaching on its boundaries on every side. 
However, Scott’s partly unsympathetic portrait of Alexius, as devious, cunning and treacherous, is derived from hostile western sources, such as the anonymous Gesta Francorum, or to give its full title, Gesta Francorum et aliorum Hierosolimitanorum ("The deeds of the Franks and the other pilgrims to Jerusalem") which is a Latin chronicle of the First Crusade written in about 1100-1101, and was probably as Sir Steven Runciman claims, “a diary [written] by one of Bohemond’s followers who went on to Jerusalem with Tancred. It ends with the story of the battle of Ascalon in 1099 and was first published in 1100 or early 1101…The author was a simple soldier, honest according to his lights but credulous and prejudiced and a strong admirer of Bohemond. The wide success of the Gesta was mainly due Bohemond’s own efforts. He regarded it as his apologia and himself hawked it round northrn France during his visit there 1106.” Equally hostile is Raymond of Aguilers [in the Haute –Loire, France] who “joined the Crusade in the company of Adhemar of Le Puy, and soon became chaplain to Raymond of Toulouse. He began to write his chronicle, the Historia Francorum qui ceperunt Jerusalem, [History of the Franks who Captured Jerusalem] during the siege of Antioch and finished it at the end of 1099….Only on one occasion does he mention the Greeks without an unfriendly comment.”
Here is Scott’s delineation of Alexius: “…if he commonly employed cunning and dissimulation instead of wisdom, and perfidy instead of courage, his expedients were the disgrace of the age rather than his own….Such a mixture of sense and weakness, of meanness and dignity, of prudent discretion and poverty of spirit, which last, in the European mode of viewing things, approached to cowardice, formed the leading traits of the character of Alexius Comnenus, at a period when the fate of Greece, and all that was left in that country of art and civilization, was trembling in the balance, and likely to be saved or lost, according to the abilities of the Emperor for playing the very difficult game which was put into his hands.” 
Scott ridicules the Byzantine court which was “encumbered with unmeaning ceremonies” -- ceremonies described by Anna in the Alexiad. However, Scott does concede Alexius’s courage in battle, and believes that perhaps Alexius was the right man to lead the Greeks at that moment in history.
 Anna Komnene The Alexiad. London: Penguin Books, Revised Edn. 2009, Book X, p.275.
 Anna Komnene, op.cit., Book X, p.277.
 Anna Komnene, op.cit. Book X, p. 285.
 Count Robert of Paris, p.131
 Count Robert of Paris, p.35
 Count Robert of Paris, p.37
 Count Robert of Paris, pp.35-38.
To be continued.