The battle of Ankara or Angora (28 July 1402) was a major victory won by Tamerlane over the Ottoman Army of Sultan Bayezid that nearly destroyed the Ottoman Empire, and as a side-effect gave the Byzantine Empire another fifty years of life.
By 1402 Bayezid and Tamerlane (or Timur the Lame) had both established a fearsome reputation as conquerors. Tamerlane had created a large empire in Transoxiana and Persia, while Bayezid had expanded the Ottoman Empire in Europe and in Anatolia, and had won a famous victory over a European crusading army at Nicopolis. It was perhaps inevitable that the two men would end up fighting each other, each seeing the other as a threat to their flanks. Both courts contained refugees from the other's conquests - Bayezid had sheltered Sultan Ahmad Jalayir, the former ruler of Baghdad, while many of the Anatolian princes defeated by Bayezid were with Tamerlane.
The first outright clash between the two powers came in 1401, when Tamerlane captured the city of Sivas, in eastern Anatolia. This was at the eastern end of Bayezid's empire, and had only recently been captured by the Ottomans.
Tamerlane spent the winter of 1401-02 in Karabakh, on the border between Armenia and Azerbaijan. Realising that he had to eliminate the threat from Tamerlane, Bayezid lifted the siege of Constantinople, and gathered a large army with Balkan and Anatolian contingents. He decided to try and force Tamerlane to fight somewhere between Karabakh and eastern Anatolia, but he was outmanoeuvred.
As the Ottoman army approached Ankara Tamerlane moved west, reaching Sivas. Bayezid's advisors suggested that he should stop at Ankara, where there was a good water supply, and wait for Tamerlane to come to him, but Bayezid rejected this advice and continued to advance east.
While the Ottoman army moved east, Tamerlane left Sivas and marched south-west along the Kizilirmak River. Six days of forced marches brought him to Kayseri, where he rested for four days before moving on to Kirsehir. From there he advanced north-west, reaching Bayezid's old camp at Ankara. Tamerlane was now between Bayezid and the heart of the Ottoman Empire.
While Tamerlane settled down to besiege Ankara, Bayezid realised that he was in trouble and began a series of forced marched back west towards Ankara. When the Ottomans reached the city they found that Tamerlane had spoiled the only water supply available to them, and was arrayed for battle
There is no consensus as to the size of the two armies at Ankara. Johann Schiltberger, a Christian who had been captured after Nicopolis, entered Ottoman service and who was present at the battle, gave the highest figures, suggesting that Tamerlane had 1,600,000 men and the Ottomans 1,400,000. At the opposite extreme more modern studies have suggested that neither side could have had more than 20,000 men given the speed of their movements and the terrain they were crossing.
The Ottoman force was drawn up with Bayezid and his elite Janissary infantry in the centre, and a Serbian contingent under his brother-in-law Stephen Lazarevic on the right. Much of the Ottoman cavalry was supplied by the Anatolian contingents.
Tamerlane's force was largely made up of cavalry, with some Indian elephants in the centre. His army contained a number of the Anatolian leaders whose men were now fighting for Bayezid.
At first the battle was very even. The Janissaries were able to hold their own in the centre, while the Serbs pushed back Tamerlane's left. The deciding moment came when Bayezid's Anatolian troops began to leave the field or even chance sides. Under attack from both side most of the Ottoman army fled the field. The Serbs held on for a little longer before they were forced to retreat, leaving Bayezid and the Janissaries to stand alone. Even then they were able to hold on until nightfall, when the last 300 men attempted to escape. Tamerlane's cavalry quickly caught them, and Bayezid was captured after his horse was killed under him.
In the aftermath of the battle Tamerlane was not quite his ruthless self, and many of the Ottoman survivors were able to escape across the Sea of Marmara to the empire's European provinces (Bayezid's son Suleiman escaped on a Genoese ships, while others were helped across the water by the Byzantines!). Tamerlane advanced across Anatolia, storming the Crusader stronghold at Smyrna towards the end of the year. Manuel II, the Byzantine Emperor, offered his submission to Tamerlane, as did Suleiman. Bayezid himself was kept prisoner, and accompanied Tamerlane's court until his death on 8 March 1403.
The battle of Ankara was a crushed blow for the Ottoman Empire, but it recovered with surprising speed. None of the Ottoman's local rivals were able to take advantage of Tamerlane's brief eruption into Anatolia, and only fifty years later the Ottomans finally conquered Constantinople, ending the Byzantine Empire. Tamerlane himself only survived for another four years, dying in 1404 on his way to invade China.