On 7 August, a fleet of Sasanian rafts ferrying troops across the Bosphorus was surrounded and destroyed by Byzantine ships. The Slavs under the Avars attempted to attack the sea walls from across the Golden Horn, while the main Avar host attacked the land walls. Patrician Bonus' galleys rammed and destroyed the Slavic boats; the Avar land assault from 6 to 7 August also failed. With the news that Theodore had decisively triumphed over Shahin (supposedly leading Shahin to die from depression), the Avars retreated to the Balkan hinterland within two days, never to threaten Constantinople seriously again. Even though the army of Shahrbaraz was still encamped at Chalcedon, the threat to Constantinople was over.