The only documented record of Wren's military service records his appointment on 1 December 1914 as a reserve officer attached to an Indian infantry regiment - the 101st Grenadiers.
101st Airborne Division | 101st United States Congress | 101st Airborne Division (United States) | Regiment of Mounted Grenadiers | Grenadiers à Cheval de la Garde Impériale | 102nd Prince of Wales's Own Grenadiers | 101st meridian west | 101st Grey Cup | The Winnipeg Grenadiers | 101st meridian east | 101st Grenadiers |