 The veteran units were expected to form a core of experienced soldiers in the local defenses, whose expertise would be invaluable to the regular militiamen who often lacked sustained military experience, if any.The veteran units were created in the past century as part of the Bourbon Reforms to reinforce Spanish America's defenses against the increasing encroachment of other European powers, such as during the Seven Years' War.Overall, Europeans formed only about a tenth of the royalist armies in Spanish America, and only about half of the expeditionary units.