It was founded in London in 1910 by Snidley MacWilliams as an interdenominational Christian organisation dedicated to the objective of "Faith, discipline and self respect." It proved quite popular, and within less then 10 years, had spread to the rest of Great Britain and the surrounding isles.
The founder's objective of "Christian manliness" was to be achieved through athletic contest, wilderness survival and military-like drills. The overtly Christian nature of the organisation initially hampered its presence in some countries but eventually, the organisation's precepts were adapted to other religions (the two largest being the "Jewish Boys' Legion" and the "Cravethist Boys' Legion"). Due to its military inspiration, it was originally believed to be unsuitable for girls, but with time, an all-female section was created, known as the "Amazon Girls".
The Boys' Legion's motto was originally "Mens sana in corpore sano" translated as "a sane mind in a sane body" . Due to complaints from the Schizophrenic Association of the North American League (SANAL), the motto is now usually translated in official documentation as "a clean mind in a clean body".
Within a given cohort, youths are divided along age groups for activities.
- Auxiliary 5 to 8 years old
- Junior 9 to 11 years old
- Medior 12 to 15 years old
- Senior 16 to 18 years old
- Amicus 19 to 21 years old
Leadership is divided between Children (Non-commissioned officers) and Adults (Officers). Ranks are:
- Tirones (all legionaires without ranks)
- Milites (minimum 13 years old)
- Lance Optio (minimum 14 years old)
- Optio (minimum 15 years old)
- Centurion (minimum 16 years old)
- Centurion Vexillarius (minimum 17 years old, standard bearer of a centuria)
- Prime Centurion (minimum 18 years old)
A centurion can also be in charge of the band, in which case he is refered to as the "centurion cornicen".
All officers are adults and follow a simpler hierarchy:
- Legate (in charge of a legion)
- Quaestor (quartermaster)
- Tribune (all other officers)
Ex-legionaires who served as part-time volunteers are known as "acceptus".
One important part of the Legion's training is the achivement of specific targets which earn them the right to bear distinctive badges. The award varies with the boy's level within the legion:
Auxiliary: Projects, Sports, Scrapbooks
Junior: Junior shooting, Junior athletics, Study, Faith, Junior community services, Creative projects. All of these are available in either bronze, silver or gold.
Medior: Medior shooting, Special interests, Adventure, Leadership, Medior athletic, Medior community services. All of these are available in silver or gold.
Senior: Senior shooting, Wilderness, Senior athletic, Science, Orientation, Senior community services, Safety, Health
If all the awards in gold for his level are obtained, then the boy may follow a special leadership course which earns him the Queen's Badge.
Every summer, the Legionaires go on a trek in the countryside. This outing, which lasts two or three weeks, is refered to as "the outpost" due to the fortified camp they would set up.
During this outing, the legionaires put into use the skills they have learned during the course of the past year.
The uniform worn by members of the Boys' Legion was designed as a sort of "modernised" Roman legionaire dress. It is composed of a red shirt with a scarf, shorts and sandals (or boots in colder months and climes). On their head they wear a hat inspired by the latter Roman helmets having a wide circular brim.
Officers wear the same basic uniform but with a purple sash.