hermandad (ārmändäŧħ´) [Span.,=brotherhood], a peacekeeping association of armed individuals, a characteristic of municipal life in medieval Spain, especially in Castile. Hermandades are known to have existed as early as the 12th cent. Since the medieval Spanish kings were for the most part unable to offer adequate protection, protective municipal leagues against bandits and other rural criminals, as well as against the lawless nobility, began to emerge in the 12th cent. These bodies, at first temporary but eventually permanent, took into custody and summarily tried suspects. Among the most powerful was the league of N Castilian and Basque ports, the Hermandad de las Marismas, formed in 1296 to safeguard domestic and foreign trade. The crown had limited success in regulating the activities of the hermandades. As one of their first acts after the war of succession, Ferdinand and Isabella established the centrally organized and efficient Holy Hermandad (Span. Santa Hermandad), which suppressed the original hermandades. Especially effective in rural Castile, this combined rural constabulary and judicial tribunal ensured personal security and public order, serving the additional purpose of reasserting royal jurisdiction and curbing aristocratic power; middle- and lower-class taxpayers assumed the cost. Each town provided archers and militia, and the tribunals consisted of unpaid local judges (alcaldes). Ferdinand expanded the Santa Hermandad to Aragon. A supreme council under the bishop of Cartagena as royal representative oversaw the entire organization. Although the Santa Hermandad soon achieved its purpose, the Spanish rulers, who had found it indispensable in fighting the Moors as well, kept the supreme council until 1498. Hermandades continued to serve as modest local police units until their suppression in 1835.