I can't resist sharing this image, even though I don't know much about where it comes from or the people in it. If anyone does please let me know. In a mix of Ottoman and French it shows a number of powerful figures from the Ottoman court with their titles, all originally derived from rather menial positions in the palace staff, as well as the more important duties they assumed in time. The Segban Bachi, or Head of the Hounds, is described as the Head Officer of the Janissaries. Next is the Bostandji Bachi, or Head Gardner, followed by the Sou Bachi, or Chief Waterer, now a leader of the Gendarmerie. The Assas Bachi is, in addition to his duties as a Janissary Captain, charged with reading out the sentences of the condemned, while the Bodjek Bachi, who I assume would originally been in charge of protecting the royal garden from invasive insects, is apparently responsible for investigating thefts. Obviously the most outstanding questions all involve their hats. To my knowledge no one, not even Reşat Ekrem Koçu, has written anything comprehensive on the history and symbolism of Ottoman headgear, though I certainly hope to be proven wrong.
* Sada Payir was kind enough to send in the picture (left) from page 11 of 'İslamda Başlık' by Orhan Koloğlu, available for 22 liras on nadirkitap. This page alone offers a remarkably comprehensive guide to Ottoman hats, and might be a better use of your money than Traktat über die Derwischmützen (Risāle-i Tāciyye) des Müstaqīm-zāde Süleymān Sādeddin, a more scholarly and more german work brought to our attention by Selim Kuru and priced online at 142 pounds.