Serbia in the Middle Ages had an army that was well known for its strength and was among the strongest in the Balkans prior to the Ottoman conquest of Europe. Prior to the 14th century, the army consisted of European-style noble cavalry armed with bows and lances (replaced with crossbows in the 14th century) and infantry armed with spears, javelins and bows. With the economic growth from mining, mercenary knights from Western Europe were recruited to finalize and increase the effectiveness of the army, especially throughout 14th century.
History
Early Middle Ages
Between 839 and 842 the Bulgar Khan Presian invaded inland parts of the Serbian territory, the two having lived peacefully sharing a common frontier up until that point. The cause for the invasion is unclear. It led to a war that lasted three years, in which the Bulgars were decisively defeated. In the mid 850s the Bulgarians under Boris I made another unsuccessful attempt to subdue the Serbs. In the beginning of the 10th century Simeon I launched several campaigns against the Serbs who were acting as Byzantine allies and by 925 he managed to conquer Serbia completely but the Bulgarian rule was short-lived. Samuel of Bulgaria subjected the Serbs for a second time in 1009 or 1010 after he defeated their ruler Jovan Vladimir.
10th-century Byzantine military manuals mention chonsarioi, light cavalry formations recruited in the Balkans, especially Serbs, "ideal for scouting and raiding". These units are considered a precursor of Hussar cavalry formations later found in Hungarian and Polish armies.
Late Middle Ages
12th century
The writings of John Kinnamos and other contemporary Byzantine sources (Anna Komnene, Niketas Choniates, Eustathios of Thessalonica, Michael of Thessalonica) of the twelfth century, gives substantial data concerning Serbian armament and tactics.Drašković, M. 2010, "Serbian armament and tactics in writings of John Kinnamos", Vojno-istorijski glasnik, no. 2, pp. 9-19.
As primary weapons of the Serbs, Kinnamos mentions spears and long shields. The terms he uses for these weapons (borata and aspibaz) are the words which, in Kinnamos' writings and contemporary Byzantine sources denote spears and shields in general meaning; so, it is not possible to determinate from Kinnamos the type of spears and shields that were used by Serbs of twelfth century. Michael of Thessalonica attests Serbian usage of spears and shields in twelfth century, also by terms of general meaning. Kinnamos mentions Serbian usage of sword. The term he uses for sword (xifoz) is the word which in his writings denotes sword in general meaning; because of that, it is not possible from this term to determinate the type of sword which was used by Serbs of twelfth century. But, in one of his orations, N. Choniates uses word romfaia to name sword used by Serbs. Since term romfaia in Byzantine sources usually denotes one-edged sword, and since Choniates calls sword in general meaning by word xifoz, it is reasonable to suppose that some Serbs of twelfth century used one-edged sword. Surprisingly Kinnamos doesn't mention Serbian usage of bow and arrows, although Serbian usage of arrows is known from the previous epochs. This circumstance may be attributed to fragmental character of Kinnamos' data concerning foreign nations, or to Kinnamos' impression that arrows don't play vital role in Serbian warfare. Kinnamos doesn't mention armor among Serbs, but, when talking about battle of Tara (1150) he says that Serbs were well armed using word katafraktoz which usually means 'armored'. Presence of armor among Serbs of twelfth century could be attested by Michael of Thessalonica who mentions Serbs using mail face-coverings, and we know that such mail masks were usually integral part of mail hauberks. Kinnamos mentions Serbian 'hoplites' in fortress of Galič; since, in Kinnamos writings, term 'hoplite' denotes heavy armed and armored infantryman, this mention of 'hoplite' could also indicate presence of armor among Serbs of twelfth century. Eustathios of Thessalonica also mentions hoplites in Serbian army. Concerning Serbian tactics, Kinnamos also offers interesting fragments. One part of Serbian army fighting in battle of Tara, Kinnamos shows fighting as infantry. Serbian infantry of twelfth century is attested by Eustathios of Thessalonica, but it is important that Eustathios also mentions Serbian cavalry, led by Nemanja. Describing battle of Tara, Kinnamos shows some parts of Serbian army using ambush and sudden strike. Serbian use of ambush is attested by Eustathios of Thessalonica, who mentions Nemanja's ambushes.
14th century
Serbia defeated the Bulgarian Empire in the Battle of Velbazhd in 1330, becoming a military superpower during the middle part of the 14th century under the dynamic Stephen Uroš IV Dušan (1331–55), who created the Serbian Empire. It included Macedonia, Albania, Epirus and Thessaly, reaching from the Drina and Danube rivers as far south and east as the Gulf of Patras and the Rhodope Mountains by 1350. A large part of this expansion was at the expense of the Byzantine Empire. Dušan set his sights on the Byzantine capital of Constantinople itself, dividing his lands into 'Serbia' and 'Romania'. Dušan was crowned Emperor (Tsar) of Serbs and Romans in 1346. He modeled his court on that of Constantinople, calling his officials by Byzantine titles such as caesar, despot, sebastokrator and logotet (logothete). However, following his death, the Serbian Empire gradually disintegrated under his successor Stephen Uroš V (1355–71). One Byzantine chronicler noted with evident satisfaction that the Serbian nobility were soon divided into '10,000 factions', while John VI Kantakouzenos wrote that Dušan's empire fell 'into a thousand pieces'.
After 1363, Vukašin Mrnjavčević became the most powerful noble in the Serbian Empire; he controlled lands in the south of the empire, primarily in Macedonia.Mihaljčić 2001, pp. 29–52 He was defeated and killed by the Ottoman Turks in 1371 in the Battle of Marica.Fine 1994, p. 379 In 1371, Prince Lazar Hrebeljanović emerged as the most powerful Serbian lord. He created the largest state on the territory of the disintegrated Serbian Empire; his state is known in historiography as Moravian Serbia. Its government and army were better organized than those of the domains of the other Serbian lords.Fine 1994, pp. 387–89Mihaljčić 2001, pp. 116–32 In 1386, Prince Lazar rebuffed the Ottoman Sultan Murad I at Pločnik, a site southwest of the city of Niš.
An Ottoman army led by Sultan Murad, estimated at between 27,000 and 30,000 men, arrived in June 1389 on the Kosovo Field near Priština. The Ottomans were met by the forces commanded by Prince Lazar, estimated at between 15,000 and 20,000 men, with a higher estimate up to 25,000, A higher estimate places the size of Murad's army up to 40,000 and Lazar's up to 25,000 troops. which consisted of the prince's own troops, Vuk Branković's troops, and a contingent sent by the King Tvrtko I of Bosnia. In the Battle of Kosovo, both Prince Lazar and Sultan Murad lost their lives. The battle was tactically inconclusive, but the mutual heavy losses were devastating only for the Serbs, who had brought to Kosovo almost all of their fighting strength. Lazar was succeeded by his eldest son Stefan Lazarević, who became an Ottoman vassal in the summer of 1390. Vuk Branković accepted Ottoman suzerainty in 1392.Fine 1994, pp. 409–14 The battle of Kosovo was one of the large battles of late medieval times. In comparison, in the battle of Agincourt (1415) even by assuming the higher estimate of army size as correct, around 10,000 fewer soldiers were engaged.Humphreys, Brendan (2013). The Battle Backwards A Comparative Study of the Battle of Kosovo Polje (1389) and the Munich Agreement (1938) as Political Myths. Later, Stefan Lazarević participated on the Ottoman side in the Battle of Rovine in 1395, the Battle of Nicopolis in 1396, and the Battle of Ankara in 1402.The Balkans, 1018-1499, M. Dinic, The Cambridge Medieval History, Vol. 4, Ed. J.M. Hussey, (Cambridge University Press, 1966), 551.
15th century Stefan Lazarević was granted the title of Despot by the Byzantine Emperor, and he ceased to be an Ottoman vassal in 1402.Fine 1994, p. 500 He introduced modern western style knight warfare and knight tournaments. And there were firearms already in use, especially in armored cavalry.Fine, The Late Medieval Balkans (1987) He ruled Serbia as Despot from 1402 to 1427. He was fighting against the Ottomans, and later he supported Mehmet I rise to power in the Battle of Çamurlu.
After him the Branković dynasty came to power. They continued developing modern military battle tactics. Despot Đurađ Branković who ruled Serbia from 1427 to 1456, constructed the Smederevo Fortress, which was the largest medieval lowland type of fortress in Europe. This fortress had 24 towers and a citadel with 50m tall towers. Most of the fortress remains intact until nowadays.
Organization The Serbian army was feudal in nature, though its system of military landholding was inherited from the Byzantine pronoia rather than the Western European fief. The pronoia itself - hereditary by some accounts, non-hereditary by others - is only first recorded in Serbia under that name in 1299 (the Serbs spelt it pronija, or pronya, and called its holder a pronijar), but even from as early as Stefan Nemanja reign (1186–96) every able-bodied man possessing a bashtina (a grant of hereditary freehold land, the holder being called a bashtinik or voynic) had been obliged to attend the army whenever required, only monastic tenants being exempted in exchange for performing part-time garrison duties in local fortresses and fortified monasteries. The building and maintenance (gradozadanje) of such fortresses, and equally the maintenance of their permanent garrisons (gradobljudenlje) was an additional aspect of the feudal responsibilities of the population of each Župa (district), who were also responsible for guarding their own frontier. The holders of both bashtinas and pronijas constituted the nobility (though many of the former were only upper-class peasants), and these were the principal native element of every Serbian army, serving as heavy cavalry (the proniiars) and infantry (the voynici), In fact most armies included only the nobility (the vlastelini, or 'holders of power') and their retinues, maintained at their own expense, but in times of emergency the arriere-ban, called the Zamanitchka Voyska ('All Together'), would be summoned. As elsewhere, this comprised all the nobility and every able-bodied freeman.
In border regions all land-grants appear to have been called krayina and their holders vlastele krayishnik ('border lords'), whose duty it was to guard the frontier. Dušan's Code of 1349 (the Zakonik, extended and completed in 1354) actually states that any damage inflicted by an invading army had to be compensated for by the border-lord through whose lands the enemy had entered, another article stating that similar pillaging committed by brigands had to be repaid seven-fold. The Byzantine chronicler Gregoras, as ambassador for Andronikos III to Emperor Dusan, encountered some krayishnici (men of a border- lord) on crossing the frontier. He wrote: 'When we passed the Struma River ... and came into thick woods, we were suddenly surrounded by men clad in black woolen garments, who darted forth from behind trees and rocks like devils out of the earth. They wore no heavy armor, being armed only with spears, battle-axes, and bows and arrows.