Instead of droning out his life in a treasury clerkship, Wellesley found a more strenuous career abroad. In the autumn of 1795 his regiment was ordered to India, where he arrived in February, 1797. A year later his already famous brother Richard, Lord Mornington, came out as Governor-general. The brothers were sincerely devoted to each other, and co-operated cordially in the important operations which followed. The English possessions in India were then limited to the coast regions, the kings and princes of the states of the interior being variously bound to the East india Company by treaty engagements. The news of the victorious progress of the French arms in Europe lost nothing by repetition in the bazaars of Hindustan, and emissaries of France were not wanting to stir the native princes against England. Bonaparte's expedition to Egypt in 1798 revealed his intention to attack England through her Indian realm. In February, 1799, the Governor-general declared war against Tippoo, Sultan of Mysore, a powerful prince, who had been plotting in the French interest. The younger Wellesley had contributed much to the efficient organization of the army which was to invade the Sultan's territory, and after the fall of Seringapatam he distinguished himself by his firm and orderly administration of the conquered domain. In 1802, the year of the Peace of Amiens, he was made a major-general. When the news of the treaty with France reached him, his opinion was emphatically expressed: "It establishes the French power over Europe, and when we shall have disarmed we shall have no security except in our own abjectness." The conquest of Mysore left only the Mahratta confederacy undominated by British authority. These states, a vast domain in western and central India, having quarreled among themselves, applied to the British for aid. General Wellesley secured the close alliance of one party, and as commander-in-chief, took the field against the others. On the 23rd of September, 1803, he found himself with seven thousand five hundred men in the presence of the Mahratta host of fifty thousand men with one hundred and twenty-eight guns. Retreat was difficult, speedy reinforcement impossible. The young major-general determined an attack immediately, and handling his little army with great skill and intrepid courage, he routed the enemy in the great victory of Assaye, which broke the Mahratta power. For his exploits he received the thanks of King and Parliament, and was dubbed a Knight of the Bath.

General Sir Arthur Wellesley returned to England in 1805, after seven years absence in India. On his way he touched at the Isle of St. Helena, and took note of its beautiful scenery and salubrious climate. Doubtless the impression then made was recalled ten years later, when it became necessary to select a safe residence for his defeated foe. To one who expressed surprise that a man of his solid achievement should receive but a subordinate post as that to which he was assigned on his return to England, General Wellesley said, "I am NIM MUK WALLAH, as we say in the East. I have eaten of the King's salt and therefore I conceive it to be my duty to serve with zeal and cheerfulness when and wherever the King or his government may think fit to employ me." This expression explains his lifelong attitude toward the crown. He considered himself its "retained servant."

It was two years before his talents were properly utilized. Meanwhile he was member of Parliament and secretary to the Lord Lieutenant of Ireland. The Peninsular War was his opportunity. Napoleon had sent Marshal Junot to Lisbon with an army to seize the country and force it into his continental system, the royal family retiring to Brazil as he advanced. At almost the same time, by a series of conscienceless machinations, he had compelled the King of Spain to abdicate, and had occupied Madrid and the fortresses of the northern provinces. In spite of popular risings against the French, Napoleon made his brother Joseph King of Spain. At once revolt flamed out among the common people, and the insurrection spread through both kingdoms, and was accepted in England as an invitation to come to their relief.

Pitt had foreseen amid the shadows of the defeat of Austerlitz that the Iberian Peninsula might be the final field of resistance to Napoleon, and now events had brought his successors to the same view. It was accessible by England's ocean highway, its people were high-spirited, and impatient of foreign domination, and a successful campaign there would threaten the French flank. In June, 1808, an expedition was dispatched to the aid of the Spanish and Portuguese insurrectionists, and the command was given to Lieutenant-General Sir Arthur Wellesley. The night before he left London he said to the friend who interrupted his reverie, "Why, I am thinking of the French. . . . 'Tis enough to make one thoughtful. But no matter; my die is cast. They may overwhelm me, but I don't think they will out-manueuver me. . . . I suspect all the continental armies were more than half-beaten before the battle was begun. I at least will not be beaten beforehand."

The qualities which fitted this officer for the heavy work in hand were those which had been developed and tested in India. He was, first of all, a worker of surpassing industry and the closest application. Where others were brilliant, he was thorough. No commander ever left less to chance or to the inspiration of the moment. He prepared for his campaigns by subjecting his troops to the most thorough drill and by providing them properly with all the munitions of war. His troops were shaped by incessant care and pains into a perfect weapon, the use of which he perfectly understood. Further than this, his experience in India, where conditions had made him the responsible administrator of vast native states, made him the right man to conduct a campaign in the peninsula, where, between the French and the Nationalists, civil administration had fallen into great disorder, and where all sorts of extraordinary tasks devolved upon the British representative. His management of his uncertain allies, the guerrilla chiefs, and his relations with the revolutionary "juntas" called for qualities as rare as those which defeated one after another of Napoleon's marshals and finally worsted the great captain himself. Thoroughness of preparation, the ability to see things as they are, to wait patiently, decide promptly, and act with energy—these are perhaps simple military virtues, but they bring success, and they were in high degree the possession of the young Indian officer, who was now to undertake a difficult campaign in a foreign country. The event proved that with such qualities a general may compass the most difficult tasks, though he may be "cold" in temperament, and incapable of kindling in the breasts of his men that passionate personal devotion which some hold to be the true test of a great soldier.

Wellesley disembarked his expeditionary force in August, at Mondego Bay, a hundred miles north of Lisbon, which Junot held with twelve thousand men. Junot advanced to meet the English, and at Vimiero Wellesley met and defeated the first of Napoleon's marshals. Before the close of the day the arrival of a superior officer terminated Wellesley's command. He had, however, inflicted such a blow that Junot was glad to sign a convention which permitted him to evacuate the kingdom. Wellesley returned to England.

In the spring of 1809 Wellesley was back in Lisbon. He had persuaded the government that Portugal could be defended and made the base of operations which should eventually clear the entire peninsula of the French. They had intrusted the chief command to him, and now left him free for four years to press his campaigns to the Spanish capital, and thence to the Pyrenees and beyond upon the very soil of France itself.

He was watched by two French armies. Soult was at Oporto in the north, and Victor far up the Tagus Valley, between him and Madrid. By an unexpected movement, having surprised Soult and sent him headlong beyond the frontier, Wellesley crossed the border in quest of Victor. The armies clashed at Talavera, in the last days of June, in one of the most stubbornly contested engagements of the war. The English kept possession of the field, and, though Joseph Bonaparte congratulated his soldiers upon the glory of the "victory," he knew in his heart, as his greater brother told him to his face, that the battle was a French defeat.

Conditions were not yet suited for an advance into Spain, where the French were gathering in enormous force, with instructions from Napoleon to "advance upon the English, pursue them without cessation, beat them, and fling them into the sea." To insure his forces against the execution of this mandate Wellesley constructed a crescent of earthworks about Lisbon, "the lines of Torres Vedras," within which he might take refuge, and under cover of which, as a last resort, his forces might be safely re- embarked for retreat. The veteran Massena was selected by the Emperor to drive the English out of Portugal. As he advanced, in the summer of 1810, Wellesley retired before him, and just when the pursuer believed the game was his, he was confronted by the impregnable lines of Torres Vedras, whose position and strength was all unsuspected. All winter Massena hovered about the hole, but the fox was safe in his earth, and in the spring the old hound again turned his face toward Spain, with the English on his trail.

For another year the English general, who, in honor of Talavera, had been raised to the peerage as Viscount Wellington, was engaged in reducing the French garrisons, and forming into useful auxiliary troops the raw Portuguese who had risen against the invader. The capture of the fortress of Ciudad Rodrigo (January, 1812) opened the road to Spain. So important was this point that the captor was rewarded for it with an English earldom, a Spanish dukedom, and a Portuguese marquisate. In early summer Wellington's army took the offensive on Spanish soil. Marshal Marmont's army at Salamanca in the north was his first objective. The clash came on the 22nd of July. On the second day of the battle of Salamanca the English infantry crushed the weakened center of Marmont's line, the marshal was wounded, his army hurriedly retreated. On the 12th of August the English were in Madrid. The Bonaparte King fled from his capital, whose citizens, intoxicated with joy, crowded around the English general, hung on his stirrups, touched his clothes, and throwing themselves on the earth, blessed him aloud as the friend of Spain!