Siege of July 1203 Fourth Crusade

the crusader attack on constantinople, venetian manuscript of geoffreoy de villehardouin s history, c. 1330

to take city force, crusaders first needed cross bosphorus. 200 ships, horse transports, , galleys delivered crusading army across narrow strait, alexios iii had lined byzantine army in battle formation along shore, north of suburb of galata. crusader knights charged straight out of horse transports, , byzantine army fled south. crusaders followed , attacked tower of galata, held northern end of massive chain blocked access golden horn. laid siege tower, byzantines counterattacked initial success. crusaders rallied, , byzantines retreated tower, crusaders able follow soldiers through gate , took tower. golden horn lay open crusaders, , venetian fleet entered. crusaders sailed alongside constantinople 10 galleys display would-be alexios iv, walls of city citizens taunted puzzled crusaders, had been led believe rise welcome young pretender alexios liberator.

on 11 july, crusaders took positions opposite palace of blachernae on northwest corner of city. first attempts repulsed, on 17 july, 4 divisions attacking land walls while venetian fleet attacked sea walls golden horn, venetians took section of wall of 25 towers, while varangian guard held off crusaders on land wall. varangians shifted meet new threat, , venetians retreated under screen of fire. fire destroyed 120 acres (0.49 km) of city , left 20,000 people homeless.

alexios iii took offensive action, leading 17 divisions st. romanus gate, vastly outnumbering crusaders. alexios iii s army of 8,500 men faced crusaders 7 divisions (about 3,500 men), courage failed, , byzantine army returned city without fight. unforced retreat , effects of fire damaged morale, , disgraced alexios iii abandoned subjects, slipping out of city , fleeing mosynopolis in thrace. imperial officials deposed runaway emperor , restored isaac ii, robbing crusaders of pretext attack. crusaders in quandary of having achieved stated aim while being debarred actual objective, namely reward younger alexios had (unbeknownst byzantines) promised them. crusaders insisted recognize authority of isaac ii if son raised co-emperor, , on 1 august latter crowned alexios angelos iv, co-emperor.