 As a result of the Battle of Jerusalem of December 1917 , the British Empire 's Egyptian Expeditionary Force captured the Holy City , bringing it under Christian control for the first time since the Crusades . As Prelate of the Venerable Order of Saint John , Lang led a service of celebration on 11 January 1918 at the Order 's Grand Priory Church , Clerkenwell . He explained that it was 917 years since the Order 's hospital had been founded in Jerusalem , and 730 years since they were driven out by Saladin . " London is the city of the Empire 's commerce , but Jerusalem is the city of the soul , and it is particularly fitting that British Armies should have delivered it out of the hands of the infidel . " 
