 The notes were handed to two horsemen who were standing by . The Manchester and Salford Yeomanry were stationed just a short distance away in Portland Street , and so received their note first . They immediately drew their swords and galloped towards St Peter 's Field . One trooper , in a frantic attempt to catch up , knocked down a woman in Cooper Street , causing the death of her son when he was thrown from her arms ; two @-@ year @-@ old William Fildes was the first casualty of Peterloo . 
