The two Carlist wars are probably the least remembered, outside Spain, of the civil conflicts of the country. In the first of these, as in 1936, foreign volunteers fought on both sides, among them the 10,000 men of the British Auxiliary Legion, an arm of Palmerston's foreign policy supporting the liberal Cristino cause and the young Queen Isabella II against her uncle, Don Carlos, pretender to the throne. With the Foreign Enlistment Act suspended in 1835, troops were recruited in Britain and Ireland to fight in a savage struggle. Ill-paid, poorly supplied and inadequately accommodated in appaling weather, the Legion suffered heavy mortality from typhus, yet fought bravely in battle, contributing to an eventual Cristino victory. Ireland played a prominent role in the Legion with four designated Irish regiments and many more men serving in other units.

The First Carlist War broke out after the death of King Ferdinand VII, the king restored at the end of the Peninsular War thanks to Wellington's victory. The crown was claimed by both his daughter Isabella, backed by the Liberal party and his brother Don Carlos, at the head of northern ultra-conservatives centred in the Basque provinces and Navarre. The Liberals or 'Cristinos' were supported by a 10,000-strong British Legion of volunteers led by a former aide to Wellington as well as the British Royal Navy, a Portuguese division, and the French Foreign Legion. With both armies still using Napoleonic weapons and tactics, early victories were won by the Basque general Zumalacarregui. After his death in 1835 a see-saw series of campaigns followed, fought by conventional armies of horse, foot and guns, supported by many irregulars and guerrillas. This little known multi-national campaign provides a fascinating postscript to the Peninsular War of 1808–14, and its uniforms present a colourful and varied spectacle.

The story of the doings of the British Legion under Sir de Lacy Evans in Spain is but little known. The expedition was a failure, and that from no want of heroic courage on the part of the soldiers, but from the most scandalous neglect and ill-treatment by the Government of Queen Christina. So gross was this neglect that within six months of their arrival in the Peninsula nearly five thousand, that is to say half the Legion, had either died from want, privation, or fever in the hospitals of Vittoria, or were invalided home. The remainder, although ill-fed, ill-clothed, and with their pay nine months in arrear, showed themselves worthy of the best traditions of the British army, and it was only at the end of their two years' engagement that, finding all attempts to obtain fair treatment from the Government unavailing, they took their discharge and returned home.The history of their doings as described in the following story is largely founded on a pamphlet by Alex. Somerville, a man of genius who enlisted in the Legion; and the events subsequent to its disbandment are taken from the work of Major Duncan, one of the Commissioners appointed by the British Government to endeavour to see that the conditions of a convention entered into by our Government and the leaders of the contending parties in Spain were duly observed--a convention, however, that had very small influence in checking the atrocities committed by both combatants.

Spain's First Carlist War was an unlikely agent of modernity. It pitted town against country, subalterns against elites, and Europe's Liberal powers against Absolute Monarchies. This book traces the individual, collective and international experience of this conflict, giving equal attention to battle fronts and home fronts.