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.^[3]

• 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.^[3]
• 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.^[3]
• 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.^[3]

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.^[4] He was defeated and killed by the Ottoman Turks in 1371 in the Battle of Marica.^[5] 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.^[6][7] In 1386, Prince Lazar rebuffed the Ottoman Sultan Murad I at Pločnik, a site southwest of the city of Niš.^[8]

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.^[9] 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.^[7][10] 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.^[11] 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.^[12]

15th century

Stefan Lazarević was granted the title of Despot by the Byzantine Emperor, and he ceased to be an Ottoman vassal in 1402.^[13] He introduced modern western style knight warfare and knight tournaments. And there were fireweapons already in use, especially in armored cavalry.^[14] 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.

Cavalry

Gusar light cavalry forces were part of the medieval Serbian military. Armed with spears and pentagonal wood shields padded with metal, they supported the noble knights as their second line on the battlefield.^[18] In the middle of each wooden shield, there was a round metal knob that held the shield together.

Gusar light cavalries were a traditional Serbian force, which meant that they usually were not hired as mercenaries from Spain or Germany. Their style of fighting was similar to the noble knights. They used the eastern style of fighting: they would charge into the enemy ferociously, and try to cause mass havoc. As for their role with the foot soldiers, they were more like support cavalry. When the foot soldiers were losing the battle, the Gusars would charge into the enemy's flank, hoping to cause them to rout. They would repeat this charge from different angles while the infantry kept the enemy from chasing the Gusars.

Later on, after the fall of the Serbian Empire, these troops were used as "Krajišnici" meaning frontiersman in the Habsburg Monarchy (today Croatia, Slavonia, Vojvodina) which southern parts became the military frontier, defending and liberating as they believed Christendom from the Ottoman invasion. Their military tactics of engaging combat, as well as pillaging and looting of Ottoman ruled territories, were similar to the ones of the Cossacks.

According to Webster's the word hussar stems from the Hungarian huszár, which in turn originates from the Serbian хусар (Husar, or гусар, Gusar) meaning pirate, from the Medieval Latin cursarius (cf. the English word corsair).^[19] A variant of this theory is offered by Byzantinist scholars, who argue the term originated in Roman military practice, and the cursarii (singular cursarius).^[20] Through Byzantine Army operations in the Balkans in the 10th and 11th centuries when Chosarioi/Chonsarioi were recruited with especially Serbs,^[21] the word was subsequently reintroduced to Western European military practice after its original usage had been lost with the collapse of Rome in the west.^[22]

The hussars reportedly originated in bands of mostly Serbian warriors ^[23] crossing into Kingdom of Hungary after the Ottoman invasion of medieval Serbian state at the end of the 14th century. The Governor of Hungary, Hunyadi János – John Hunyadi, created mounted units inspired by his enemy the Ottoman Turks. His son, Hunyadi Mátyás Matthias Corvinus, later king of Hungary, is unanimously accepted as the creator of these troops. Initially they fought in small bands, but were reorganised into larger, trained, formations during the reign of King Matthias Corvinus.^[24][25] Initially the first units of Polish hussars in the Kingdom of Poland were formed in 1500, which consisted of Serbian mercenaries.^[26]