The first shot memorial is the common name of a monument in Casteau, Belgium, marking the first British engagement on the Western Front of the First World War. The monument stands near to the start of a charge made by elements of C Squadron of the 4th (Royal Irish) Dragoon Guards, commanded by Captain Charles Beck Hornby, against cavalry scouts from the German 9th Cavalry Division on 22 August 1914. A number of Germans were sabred and captured before the unit came under fire from a larger German force. The British dismounted and returned fire, with Drummer Edward Thomas firing the first shot by British troops on this front of the war, before withdrawing.