Absolutely. The folks of the middle ages were extremely familiar with the classical literature of antiquity, and the life of Julius Cesar. Almost from the get-go, the death of JC was a traumatic and polarizing event within the Republic. Multiple sources, especially accounts from the Funeral, show a fierce anger towards the murder of their leader. When his will was read aloud in a public forum, his passionate supporters were whipped into frenzy and took off to revenge his death (unsuccessfully) (1). After JC’s death, his heir Octavian takes the throne and firmly establishes the Julian line within the Roman emperor role. As time goes on, Julius Caesar is deified and his presence in the culture of Late Antique Rome becomes pervasive. As a result, there was a ton of material related to the man, his life, and his legacy. (2)
The people of medieval Europe (including the Royalty) did see themselves as the direct inheritors of the Classical tradition and consumed classical literature widely. Throughout the middle ages and well into the Renaissance period, European, Byzantine, and Arabic translators would copy famous classical works at the demand of their wealthy patrons - including the works related to JC. Over time, Julius Caesar becomes a chivalric figure - a pre-Christian example of valor, wisdom, and generosity; in other words, a truly "model king" by the standards of the time. In fact the term Cesarean Section, is named for him in the medieval period, where the baby Gaius is safely removed from the opening of his deceased mothers' abdomen. Surprisingly (or not?) this was considered an achievement on his behalf. (3)(4)
Because of this slow valorization of Julius Caesar, by the time we get to Dante's period, his legend is firmly intact. The idea that he was murdered by his own statesmen would likely be seen as horrific and evil - an extreme example of regicide. The assassins WOULD belong in the depths of hell in the popular imagination. This fascination with Julius Caesar continued and his life was still in the public consciousness in Shakespeare’s time and still exists now. I mean, we are on the internet talking about it, so...joke's on the guys who killed him in an attempt to erase his legacy, I guess!
Appian: The Funeral of Julius Caesar, 44 BCE William Stearns Davis, ed., Readings in Ancient History: Illustrative Extracts from the Sources, 2 Vols. (Boston: Allyn and Bacon, 1912-13), Vol. II: Rome and the West, pp. 154-158. Scanned by: J. S. Arkenberg, Dept. of History, Cal. State Fullerton. Prof. Arkenberg has modernized the text.
Department of Medieval Art and The Cloisters. “Classical Antiquity in the Middle Ages.” In Heilbrunn Timeline of Art History. New York: The Metropolitan Museum of Art, 2000–. http://www.metmuseum.org/toah/hd/anti/hd_anti.htm (October 2001)
Ibid.;
Wyke, Maria. Caesar, A Life in Western Culture http://press.uchicago.edu/Misc/Chicago/921532.html
Hi there! I think we need to keep in mind Dante was writing before the invention of the printing press; his intended audience was a very small, very well-educated elite. I actually wrote a similar answer to the question "Would the average Italian citizen have been able to understand all the references in Dante's Divine Comedy when it was first written?"
Dante was writing a poignant condemnation of his peers in an enormously complicated religious allegory. He was writing for a hyper-educated elite which had cast him out, disregarding his loyalty to his city (incidentally, this is also why his references go so far beyond tuscan politics: the courts at Ravenna, Rimini and Verona had welcomed him). The Divine Comedy, as a study of morality, damns Dante's enemies using a system of allegories to show them just how immoral they are, and touts the virtues of those who had instead helped and welcomed him. Italian politics at the time consisted of highly elaborate political games that pitted family against family fighting for dynastic supremacy in a surprisingly malleable world.