وقعة نهر الماريتسا (صيرمن)

The battle of the Maritsa river (Sırpsındığı) in Murad I's reign — al-Sallabi describes a coalition of Balkan kings, Serbs, Bulgarians, Bosnians and others, mustering near a hundred thousand on the river by Edirne, when Lala Şahin's small Ottoman force struck the camp in the dark before dawn and destroyed it, the fleeing soldiery drowning in the river ¹.

The victory opened the Balkans to the Ottomans; the book says its news reaching Cairo was met with seven days of public celebration ².