Landing at La Paz, in the southwestern corner of the Gulf of California, with his few companions, he captured a number of hamlets and then grandiloquently proclaimed Lower California an independent state and himself its president. His next proclamation "annexed" to his territory the large Mexican state of Sonora, on the mainland opposite the California Gulf, and for a brief period he posed among the sparse inhabitants as a ruler. Some reinforcements reached him by water, but another party that started overland was dispersed by starvation, their food giving out.

Walker now set out with his buccaneering band on a long march of six hundred miles through a barren and unpeopled country towards his "possessions" in the interior. The Mexicans did not need any forces to defeat him. Fatigue and famine did the work for them, desertion decimated the band of invaders, and the hopeless march up the peninsula ended at San Diego, where he and his men surrendered to the United States authorities. Walker was tried at San Francisco in 1854 for violation of the neutrality laws, but was acquitted.

This pioneer attempt at invasion only whetted Walker's filibustering appetite. Looking about for "new worlds to conquer," he saw a promising field in Nicaragua, then torn by internal dissensions. Invited by certain American speculators or adventurers to lend his aid to the democratic party of insurrectionists, he did not hesitate, but at once collected a band of men of his own type and set sail for this new field of labor and ambition. On the 11th of June, 1855, he landed with his small force of sixty-two men at Realijo, on the Nicaraguan coast, and was joined there by about a hundred of the native rebels.

Making his way inland, his first encounter with the government forces took place at Rivas, where he met a force of four hundred and eighty men. His native allies fled at the first shots, but the Americans fought with such valor and energy that the enemy were defeated with a loss of one-third their number, his loss being only ten. In a second conflict at Virgin Bay he was equally successful, and on the 15th of October he captured the important city of Granada.

These few successes gave him such prestige and brought such aid from the revolutionists that the opposite party was quite ready for peace, and on the 25th he made a treaty with General Corral, its leader, which made him fairly master of the country. He declined the office of president, which was offered him, but accepted that of generalissimo of the republic, an office better suited to maintain his position. His rapid success brought him not only the support of the liberal faction, but attracted recruits from the United States, who made their way into the country from the east and the west alike until he had a force of twelve hundred Americans under his command.

General Corral, who had treated with him for peace, was soon to pay the penalty for his readiness to make terms with an invader. He was arrested for treason, on some charge brought by Walker, tried before a court-martial at which the new generalissimo presided, sentenced to death, and executed without delay.

The next event in this fantastic drama of filibusterism was a war with the neighboring republic of Costa Rica. Both sides mustered armies, and a hostile meeting took place at Guanacaste, on March 20, 1856, in which Walker was worsted. He kept the field, however, and met the foe again at Rivas, on April 11. This time he was victorious, and the two republics now made peace.

His military success seemed to have made the invader securely the lord and master of Nicaragua, and he now threw aside his earlier show of modesty and had himself elected president on June 25. He had so fully established himself that he was recognized as head of the republic by President Pierce, on behalf of the United States. But he immediately began to act the master and tyrant in a way that was likely to bring his government to a speedy end.

Money being scarce, he issued currency on a liberal scale, and by a decree he restored the system of slavery which had been abolished thirty-two years before. Not content with these radical measures within the republic itself, he was unwise enough to create for himself a powerful enemy in the United States by meddling with the privileges of the Vanderbilt Steamship Company, then engaged in transporting the stream of gold-hunters to California over a Nicaraguan route. Walker revoked their charter and confiscated their property, thus bringing against his new government a fire in the rear.

His aggressive policy, in fact, made him enemies on all sides, the Central American states bordering on Nicaragua being in sore dread of their ambitious neighbor, while the agents of the Vanderbilt Company worked industriously to stir up a revolt against this soaring eagle of filibusterism.

The result was a strong revolt against his rule, and he soon found himself confronted by a force of patriots in the field. For a short time there were busy times in Nicaragua, several battles being fought by the contending forces, the war ending with the burning of Granada by the president. Finding that the whole country was rising against him and that his case had grown desperate, Walker soon gave up the hopeless contest and surrendered, on May 1, 1857, to Commodore C. H. Davis of the United States sloop-of-war "St. Mary," who took him to Panama, where he made his way back to the United States.

Thus closed the conquering career of this minor Cortez of the nineteenth century. But while Walker the president was no more, Walker the filibuster was not squelched. The passion for adventure was as strong in his mind as ever, and his brief period of power had roused in him an unquenchable thirst for rule. In consequence he made effort after effort to get back to the scene of his exploits, and rise to power again, his persistent thirst for invasion giving the United States authorities no small trouble and ending only with his death.

In fact, he was barely at home before he was hatching new schemes and devising fresh exploits. To check a new expedition which he was organizing in New Orleans, the authorities of that city had him arrested and put under bonds to keep the peace. Soon after that we find him escaping their jurisdiction in a vessel ostensibly bound for Mobile, yet making port first in Central America, where he landed on November 25, 1857.

This effort at invasion proved a mere flash in the pan. No support awaited him and his deluded followers, and in two weeks' time he found it judicious to surrender once more to the naval authorities of the United States; this time to Commodore Paulding, who took him to New York with his followers, one hundred and thirty-two in number.

His fiasco stirred up something of a breeze in the United States. President Buchanan had strongly condemned the invasion of friendly territory in his annual message, but he now sent a special message to Congress in which he equally condemned Commodore Paulding for landing an American force on foreign soil. He decided that under the circumstances, the government must decline to hold Walker as a prisoner, unless he was properly arrested under judicial authority. At the same time Buchanan strongly deprecated all filibustering expeditions.

The result of this was that Walker was again set free, and it was not long before he had a new following, there being many of the adventurous class who sympathized warmly with his enterprising efforts. This was especially the case in the South. Thither Walker proceeded, and, inspired by his old enthusiasm, he soon organized another company, which sought to leave the country in October, 1858. He was closely watched, however, and the whole company was arrested at the mouth of the Mississippi on the steamer on which passage had been taken.

President Buchanan had issued a proclamation forbidding all such expeditions, and Walker was now put on trial before the United States Court at New Orleans. But the case against him seemed to lack satisfactory evidence, and he was acquitted.

Desisting for a time from his efforts, Walker occupied himself in writing an account of his exploits, in a book entitled "The War in Nicaragua." But this was far too tame work for one of his stirring disposition, and in June, 1860, he was off again, this time making Honduras the scene of his invading energy. Landing at Truxillo on the 27th, he seized that town and held it for eight weeks, at the end of which time he was ordered to leave the place by the captain of a British man-of-war. The president of Honduras was rapidly approaching with a defensive force. Walker marched south, but his force was too small to cope with the president's army, and he had not gone far before he found himself a captive in the hands of the Honduran government. Central America had by this time more than enough of William Walker and his methods, and five days after his capture he was condemned to death and shot at Truxillo.

Thus ended the somewhat remarkable career of the chief of filibusters, the most persistent of modern invaders of foreign lands, whose reckless exploits were of the mediæval rather than of the modern type. A short, slender, not especially demonstrative man, Walker did not seem made for a hero of enthusiastic adventure. His most striking feature was his keen gray eyes, which brought him the title of "the gray-eyed man of destiny."