After this campaign Bayezid returned to Adrianople, and there occupied himself by inflicting further humiliations on the Greek Empire. He forced Manuel to resign and imposed John, the son of Andronicus, as its Emperor. He then issued forth again with his army, in 1397, and fell like a thunderbolt on Greece, without any warning or cause of complaint. He marched with his army through Thessaly, capturing on the way Larissa and Pharsalia. He passed through Thermopylæ. The mere passage of his army sufficed to subdue Doris and Locris. His two generals, Yacoub and Evrenos, then invaded the Peloponnesus. The latter captured and pillaged Argos. Its inhabitants, to the number of thirty thousand, were sold as slaves and deported to Asia. Colonies of Turks were planted in the Morea. Theodore Palæologus, who acted as despot there on behalf of the Greek Empire, agreed to become tributary of the Sultan. Returning to Adrianople, Bayezid determined to obtain immediate possession of Constantinople. The Greek Empire had been already deprived of nearly all territory outside the walls of its capital. The Sultan opened proceedings against it by sending an envoy to the Emperor with this insulting message:— When I dethroned your predecessor, Manuel, it was not in your interest but in mine. If, then, you want to remain my friend, you must surrender your crown. I will give you any other government you may wish for. If you do not consent, I swear by God and the Prophet I will not spare a soul in your city; I will exterminate all of them. The citizens of Constantinople, rather than experience the terrible fate which they knew would befall them in the event of a successful assault by the Ottoman army, were willing to come to terms. But the Emperor, who was buoyed up by hope of assistance from the Christian Powers, refused to acquiesce in a pusillanimous surrender. He replied to the ambassador in dignified terms: “Tell your master that, feeble as we are, we know no other power to whom to address ourselves if it be not God, Who protects the feeble and humbles the powerful. Let the Sultan do what he pleases.”