The Demonstrations of Histories narrates the rise of the Ottoman Empire in the fourteenth and fifteenth centuries, until roughly the mid- 1460s, and the concurrent decline of the Byzantine Empire. Taking Herodotos as his structural model, Chalkokondyles presents detailed portraits of the (pre) histories and cultures of the various ethnic groups of the medieval world, particularly the Greeks and the Ottomans but also peoples in regions as geographically distant as England and India. Chalkokondyles's central narrative is the expansion of the Ottomans and the deeds of their rulers, of whom Mehmed II receives the most comprehensive treatment.

The Demonstrations is organized into ten Books, although the fact that Book 10 ends in mid- sentence, and occasional lacunae and grammatical errors throughout the work, have led historians to believe the history was left unfinished and unrevised. It contains three or four interpolations by another author, possibly Georgios Amiroutzes.

The Demonstrations is not openly hostile to Islam or the Ottomans, unlike some previous histories, such as that by Doukas. Instead, Chalkokondyles takes the part of a neutral observer toward the Christian and Muslim worlds. Jonathan Harris has argued that rather than explaining the fall of

Constantinople as divine punishment for Byzantine sins or a product of the mysterious workings of fate like other historians of his day, Chalkokondyles suggested that Turkish virtue played an important role in the conquests he describes. The Demonstrations is also notable in that it casts the Byzantines as “Greeks” rather than Romans. Further, Chalkokondyles does not display any particular interest in Christianity or ecclesiastical affairs. Some scholars have attributed this choice of topics to his Neoplatonist training. Chalkokondyles's rather obscure writing style imitates that of Thucydides.

Scholars now believe that Chalkokondyles began researching and writing the Demonstrations sometime in the 1450s and stopped in the mid- 1460s. Chalkokondyles seems to have relied primarily on Greek and Turkish sources, though he may also have used western sources as well. Most of his information was likely passed along orally, although he claims in one place that he had access to Ottoman budget records. Chalkokondyles almost never explicitly names his sources, however, so they remain largely obscure.