To what extent was the Ottoman expansion into Anatolia and the Balkans achieved through warfare?

The question requires that candidates consider the merits or otherwise of the view that Ottoman expansion was achieved through warfare in Anatolia and the Balkans. Candidates may refer to Ottoman success in warfare such as the capture of Adrianople (1361), Constantinople (1453) and Belgrade (1521). They may consider battles such as the Battle of Kosovo Polje (1389) and the Battle of Chaldiran (1514). Consideration of other factors, not related to warfare, may include Ottoman involvement in Byzantine factionalism, which led to the movement of Ottoman forces to the Balkans from Anatolia in 1352. Another factor was the use of marriage alliances, such as that between the Ottoman Prince Halil and the Byzantine Princess Irene in 1359. Candidates may also refer to the use of diplomacy, for example the Treaty of Edirne with Hungary (1444). The efficiency and popularity of the Ottoman regime attracted support from the population.