The Janissary Corps was established by Murad I in 1364 after the capture of Hadrianapolis from the Byzantines. It was called “The Hearth of Janissaries” (Yeniçeri Ocağı) or “The Infantry Masters” (Yaya Beyler). The Hearth was organized in ten battalions (Orta) with 100 personnel each, adding up to 1000 troops at the start. At the time of establishment there already existed a separate small unit of guards called the “Sekbans” (The Dog-keepers) for accompanying the sultan in hunting.

In 1451, due to increasing siege warfare, a stronger infantry force was required and the Hearth was expanded via a series of reforms. The first step was to integrate the Sekban units into the Hearth. At the end of the 15th century, with the inclusion of a new division called “Companies of the Commanding General” (Ağa Bölükleri), the Hearth reached its final organizational structure:

Divisions of the Janissary Corps (The Hearth)

A- Battalions of the Congregation (Cemaat Ortaları): 101 battalions (including the 35 Sekban companies -one of them cavalry- as the 65th battalion)

B- Companies of the Commanding General (Ağa Bölükleri): 61 companies