Mount Hæmus.--Thrace.--The Hebrus.--Thrace.--Valley of the Danube.--Revolt among the northern nations.--Alexander marches north.--Old Boreas.--Contest among the mountains.--The loaded wagons.--Alexander's victorious march.--Mouths of the Danube.--Alexander resolves to cross the Danube.--Preparations.--The river crossed.--The landing.--Northern nations subdued.--Alexander returns to Macedon.--Rebellion of Thebes.--Siege of the citadel.--Sudden appearance of Alexander.--He invests Thebes.--The Thebans refuse to surrender.--Storming a city.--Undermining.--Making a breach.--Surrender.--Carrying a city by assault.--Scenes of horror.--Thebes carried by assault.--Great loss of life.--Thebes destroyed.--The manner of doing it.--Alexander's moderation and forbearance.--Family of Pindar spared.--The number saved.--Efforts of Demosthenes.--The boy proves to be a man.--All disaffection subdued.--Moral effect of the destruction of Thebes.--Alexander returns to Macedon.--Celebrates his victories.