This paper addresses the military and political aspect of the Turkish siege of Constantinople in 1422 AD, when the Ottomans gained valuable experience to use it later, in the final battle of 1453. The research is based on the analysis of fifteenth-century Byzantine historical and rhetorical works. The author of this paper has reconstructed the course of the siege and the main stages of preparation to the decisive assault, has analysed the enemy’s military plans, the alignment of forces and tactical ploys of siege warfare, the specificities of Ottoman weaponry, and the sides’ actions during the assault. Attention has been paid to the Byzantines’ behaviour in the period of military conflict and the emperors’ political actions for the conflict...