Pioneer

A Pioneer is a soldier employed to perform engineering and construction tasks. The term is in principle similar to Sapper. Pioneers were originally part of the artillery branch of European armies. Subsequently, they formed part of the engineering branch, the logistic branch, part of the infantry; or even comprised a branch in their own right. Historically, the primary role of pioneer units was to assist other arms in tasks such as the construction of field fortifications, military camps, bridges and roads. Prior to and during the First World War, pioneers were often engaged in the construction and repair of military railways.

During the 20th century, British Commonwealth military forces came to distinguish between small units of "assault pioneers" belonging to infantry regiments and separate pioneer units (as in the former Royal Pioneer Corps). The United States Marine Corps has sometimes organised its sappers into "Pioneer Battalions". Also historically, British infantry regiments maintained small units of pioneers for heavy work and engineering, especially for clearing paths through forests and for leading assaults on fortifications. These units evolved into assault pioneers. They also inspired the creation of the Royal Pioneer Corps.

During the First World War each division was allocated a pioneer infantry battalion, who in addition to being trained infantry were able to conduct pioneer duties. These pioneer battalions were raised and numbered within the existing infantry regiments; where possible recruits were men who possessed transferable skills from civilian life.