The Indian Army Corps of Engineers has a long history dating back to the mid-18th century. The earliest existing subunit of the Corps (18 Field Company) dates back to 1777 while the Corps officially recognises its birth as 1780 when the senior most group of the Corps, the Madras Sappers were raised. The Corps consists of three groups of combat engineers, namely the Madras Sappers, the Bengal Sappers and the Bombay Sappers. A group is roughly analogous to a regiment of Indian infantry, each group consisting of a number of engineer regiments. The engineer regiment is the basic combat engineer unit, analogous to an infantry battalion. The Corps of Engineers is one of the oldest arms of the Indian Army. The origin of the Corps dates back to 1780 when the two regular pioneer companies were raised in the Madras Presidency Army.