His Battalion arrived in France on the 14th August 1914, just 10 days after the outbreak of the Great War. As part of the 1st Division Theodore would have taken part in The Battle of Mons and the subsequent retreat, including the Rearguard Affair of Etreux, The Battle of the Marne, The Battle of the Aisne, including participation in the Actions on the Aisne heights and the Action of Chivy, and The First Battle of Ypres. On the 1st November 1914 the Battalion were moved into a position between Zonnebeke Wood and Veldhoek near Ypres. Over the following week their positions were heavily shelled and the Battalion suffered a large number of casualties. It is uncertain on which day Theodore was wounded but he was taken to a General Hospital in Boulogne where he died from the effects of his wounds. He is buried in the Boulogne Eastern Cemetery, France.