These took two basic forms. Most were initially contingents supplied by tributary Balkan princes, in particular those of Serbia, Bulgaria and Wallachia, but others were actually feudal cavalry provided in exchange for timars or tax-exemptions. This latter category was comprised chiefly of the same land-owning military aristocracy as had existed before the Ottoman conquest, the members of which had been permitted to retain their lands in exchange for performing similar military service for their new masters. To a certain extent their numbers declined over the years as many embraced Islam or were evicted for misdemeanours, but even as late as 1439 John Torzelo estimated that the Christian sipahis and their retinues totalled some 50,000 men. In Albania in 1431, 60 timariots out of 335 were still Christians; similarly, in the sancak of Tirhala there were 36 Christian timariots out of 182 in 1455, and in Branicevo in Serbia 62 out of 125 were Christians. In the last case there were in addition 40 Christian crossbowmen, 217 voynuks and 503 yamaks (from jamaq, ‘companion’) under 61 lagators (see page 17). The term voynuk derived from the Serbian voynici (see page 51), in Ottoman usage indicating an armoured Balkan Christian foot-soldier (the yamaks were unarmoured) who provided his military service in exchange for certain tax-exemptions. Such troops are to be found under this name throughout the Balkans — in Albania, Bosnia, Bulgaria, Herzegovina, Macedonia, Serbia and Thessaly — and the surviving records indicate that there were considerable numbers of them. In Branicevo in 1467/8 each 5 Christian households were expected to provide one voynuk, as were each 10 households in Herzegovina in 1478, these figures probably being representative for other regions too. Mouradja d’Ohsson’s late-18th century survey of Ottoman organisation says that the voynuks were first incorporated into the Ottoman military system in 1376 by order of Murad I, while the Ottoman chronicler Sa’d ed-Din, who wrote in the 16th century but relied heavily on earlier sources, gives the same date but attributes their ‘foundation’ to the Rumelian beylerbey Kara Timurtash. In the 15th century the voynuks are recorded as providing an important element of the Ottoman army. Their overall command was placed in the hands of a voynuk bey, with individual units under ceri-bashis.
Another adopted term under which Balkan Christians could be found serving was gander, which was of Byzantine origin, being derived from kontarion (‘lance’). A manuscript of the first half of the 15th century defined a gonder as comprised of a voynuk and 2 or 3 yamaks, while another, of the second half of the century, says voynuk and 2 yamaks. Elsewhere 4 or sometimes even 5 men are mentioned, but on the whole it would appear that the gonder was a unit of 3 or 4 men comparable in many ways to the European lance except in being unmounted. A document of 1477 expects the service of a gonder per 5 households in the Branicevo and Vidin areas.
Many voynuks may have originally been those men who made up the tributary contingents which the Balkan princes had been obliged to supply, in most cases, since the 1370s or 1380s (Halil Inalcik suggests that the easy absorption of Christian elements into the Ottoman army was probably ‘facilitated... by their previous experience as auxiliary forces’). Bertrandon de la Brocquiere enumerates these contingents (‘who serve through force’) as ‘Greeks, Bulgarians, Macedonians, Albanians, Sclavonians, Wallachians, Serbians, and other subjects of the despots of that country.’ Small wonder, then, if Tamerlane did, as Doukas claims, describe Bayezid I’s army at Ankara in 1402 as mixobarbaroi, meaning half-Greek and half-Turkish — doubtless intended as a derogatory reference to the Ottoman predilection for Christian auxiliary troops. For details of contingents supplied by the Byzantines, Serbs and Wallachians, see pages 20, 53 and 57, and for other Christian auxiliaries see below, page 11.