Who Serves and Why: Eight Forces Shaped by Faith, Caste, Trade and Party

The navy of Srivijaya served a trading empire. The atlas page says it was used both to regulate shipping and to draw merchant vessels into its ports through controlled passage, and that it turned into an offensive force as rivals and pirates grew. The Mataram wars of roughly 937 to 1016 and the Chola raids after 1025 mark its long contest. Start here: a fleet whose purpose was commerce.

Founded in 1099, this army was armored feudal knights on horseback backed by a larger body of infantry archers and spearmen, with light mounted turcopoles and the military orders of the Temple and the Hospital. Faith supplied the orders and a feudal levy supplied the rest. It was effectively destroyed as a field army at Hattin in 1187.

The samurai were Japan's professional warrior class, retainers of regional lords who trained from youth in mounted archery, swordsmanship and horsemanship. The page dates their dominance to the Genpei War of 1180 to 1185. Service was hereditary until the 1873 introduction of national conscription ended it, which is the contrast with the conscript armies met later on this path.

The Golden Horde army was Mongol cavalry descended from the forces Genghis Khan gave his son Jochi, built into a conquering power under Batu Khan and the general Subutai. The page names the victories at Legnica and Mohi in 1241 and the invasion of Timur in 1396 that broke its strength. Here the force is a people on horseback, and the khanate was its state.

Established in 1506 by Pope Julius II, the Pontifical Swiss Guard drew on the reputation of Swiss pikemen and halberdiers as soldiers for hire. Many of its members died in the 1527 Sack of Rome defending Pope Clement VII. Where other mercenary units were disbanded, it persisted as the Pope's protective force, and recruitment is still restricted to Swiss Catholic men.

The United States Army traces its founding to the Continental Army, established by the Second Continental Congress on June 14, 1775. The page describes growth from a small frontier constabulary into the largest branch of the American armed forces, shaped by the mass mobilizations of the two World Wars and by the end of conscription in 1973. It is the citizen army of a republic, set against the hired and hereditary forces before it.

The Brazilian Army was designated by law in the Empire's 1824 constitution, two years after independence. The page records the Paraguayan War of 1864 to 1870, which expanded the ground forces to some 135,000 soldiers, and the Brazilian Expeditionary Force of the Italian campaign of 1944 to 1945, which won at Monte Castello. It is a national army whose first charter was a constitution.

Hezbollah is a Lebanese Shia Islamist political party with an active paramilitary wing, founded in 1982 by Lebanese Shiite clerics working closely with Iran during the civil war. The page says it fought Israeli forces until the 2000 withdrawal, took part in the 2006 war and later fought in Syria, and that in 2016 its armed strength was assessed as equal to a medium-sized army. End here: an armed force that is also a party.