During Meriño's administration General Ulises Heureaux served as minister of the interior and began to wield the power which he was to retain for twenty years. Heureaux was born in Puerto Plata about 1846. Both of his parents were negroes, his father being a Haitian who followed the sea and afterwards became a merchant, and his mother a St. Thomas woman. He received a mercantile education and took part as a subordinate in the War of the Restoration against the Spaniards. On the withdrawal of the Spaniards, in 1865, he became a bandit on the Haitian border and practised horse stealing on a large scale. Later he obtained a position in the Puerto Plata custom-house and took a more and more prominent part in the civil disturbances of his country, until he became well known as a politician and a revolutionist. He distinguished himself by his bravery and was many times wounded. Throughout these civil wars he remained a sturdy follower of General Luperon, the successor of Santana as leader of the "Blue" party and an implacable opponent of General Buenaventura Baez, the chief of the "Reds" and of General Ignacio Maria Gonzalez, the leader of the "Greens." When General Luperon overthrew President Cesareo Guillermo, in 1879, Heureaux was closely associated with the revolutionary movement.

Heureaux was able to strengthen himself to such an extent that when, in 1882, Luperon determined to become president himself he found that his former follower had outgrown him in power. The result was that Heureaux became president and served from September 1, 1882, to September 1, 1884. When his term expired a bitter struggle ensued with Luperon, who still retained considerable influence. Luperon's candidate was Segundo Imbert, while Heureaux supported General Francisco Gregorio Billini, who was ultimately victorious. Luperon went into exile, but later became reconciled with Heureaux and returned to die in Santo Domingo.

Billini entered upon the presidency on September 1, 1884, but became restive under the demands of Heureaux and his friends and resigned on May 15, 1885. The vice-president, Alejandro Woss y Gil, succeeded to the chief office. His term was to have expired in September of the following year, but a formidable insurrection broke out in July, 1886, under General Casimiro N. de Moya, with the object of preventing Heureaux from carrying out his design of succeeding Gil. After six months of fighting, during which the number of fatalities was happily remarkably small, Heureaux was victorious, and having had himself re-elected, resumed the presidency on January 6, 1887, until which time Woss y Gil remained in office.

The biennial elections were a source of annoyance even to one who was sure of victory, and Heureaux therefore called a constitutional convention which amended the constitution then in force and lengthened the presidential term to four years, beginning in 1889. As General Cesareo Guillermo, Heureaux's former companion in arms and later opponent, was understood to be nursing aspirations for the presidency, Heureaux sought to apprehend him. Guillermo fled, but finding himself pressed, committed suicide. No further obstacle opposed Heureaux's election, and he was again inaugurated on February 27, 1889.

In the meantime negotiations had been undertaken for the contracting
of new foreign loans, and one was floated in 1888 and another in 1892.
The government's fiscal agent who secured these loans in Europe was
General Eugenio Generoso Marchena, a man of much influence. In 1892
General Marchena announced himself as a candidate for the presidency.
Heureaux won without difficulty, but still uneasy, he arrested
Marchena in Santo Domingo, imprisoned him for a year and sent him to
Azua to be shot.

During Heureaux's new term, beginning in 1893, the country by improvident bond issues and debt contraction, made rapid strides in the direction of bankruptcy. In 1893, the San Domingo Improvement Company, an American corporation, under contract with the government took charge of the customs collections for the purpose of providing for the services of the loans. The illegal imprisonment of several Frenchmen gave rise to friction with the French government and in 1894 a French fleet appeared before Santo Domingo City, but the matter was adjusted by the payment of an indemnity. As the 1889 constitution forbade a president from holding office for more than two terms in succession, Heureaux, wishing to continue in the presidency, obviated the difficulty by the simple expedient of promulgating a new constitution in 1896, in which the limitation was removed. He was declared unanimously elected in 1896 and began his final term on February 27, 1897.

The long period of comparative peace enjoyed by the country under the rule of President Ulises Heureaux, or "Lilis," as the dictator was popularly known, brought seeming progress and prosperity, though at a heavy price. Many of his opponents Heureaux was able to buy, and in this way he retained the loyalty of hundreds of little military chiefs scattered through the country. Those whom he could not buy he persecuted, imprisoned, exiled, or executed. While possessing pleasant and affable manners, he was unrelenting in his persecution of conspirators and many stories are told of his harshness in this respect. It is related that when he was minister of the interior under Meriño he discovered that his brother-in-law was implicated in a plot; he therefore invited him to dinner and after they had dined, asked how his guest had enjoyed the meal. "Very well," was the answer. "I am glad of that," said Heureaux, "for I am about to have you shot. Take a cigar," he added pleasantly, "it will be your last." And it was, for the execution followed at once. On another occasion, so the story goes, after he had become president, a prominent general was his guest and after dinner they took a stroll. Coming to a place in the suburbs where workmen were digging a peculiar trench, the general inquired, "What are they digging here?" "They are digging your grave," answered Heureaux, and before the general could recover from his consternation a squad of soldiers appeared. He was shot and buried then and there. The governor of Macoris and the minister of war were both powerful men whose influence was feared by Heureaux. He therefore cunningly wrought up the latter against the former to such an extent that one fine morning the minister suddenly appeared in Macoris and had the governor summarily shot. An outcry was made by the governor's friends, and Heureaux, affecting indignation at the act, had the minister of war executed. Many of his prisoners mysteriously disappeared, and popular rumor points out one of the lower platforms of the fort "La Fuerza," where an aguacate tree formerly grew, as the place where prisoners were shot at night, their bodies being thrown to the sharks at the base of the cliff. Some of the dictator's suspects were assassinated in the public streets. Even exiles were not secure from his wrath and in one instance a Dominican writer named Eugenio Deschamps, who had been publishing articles against him in Porto Rico, was seriously wounded in the streets of Ponce by an assassin's bullet.

Ability and unscrupulousness, courage and cruelty, resolution and cunning were mingled in the character of Heureaux. Over the country he exercised the powers of an absolute monarch. He was the fountain head of all government and the real chief of every department. The accounts of the government and his private accounts were treated by him as one and the same thing. His ambition to remain in power necessitated the expenditure of large sums which he obtained through improvident foreign loans and usurious contracts with local merchants. Those whom he favored grew rich; his enemies he ruined. In other ways also his morals swerved from the straight and narrow path, and an isolated town gloried in the distinction of being the only place in the Republic where the president did not have a mistress. He himself stated that he had no concern as to what history would say of him, since he would not be there to read it.

During the latter part of Heureaux's administration the leaders of the opposition were recognized as Juan Isidro Jimenez and Horacio Vasquez, Vasquez was the chief of a large landholding family of the Cibao. Jimenez had been a prominent merchant, at one time carrying on mercantile houses in Monte Cristi, New York, Paris and Hamburg; his family had formerly been prominent in Dominican affairs, his father having been president of the Republic in 1848 and his grandfather one of the leading spirits of the revolution by which the Haitian yoke was thrown off. Jimenez was born in Santo Domingo City in 1846 and as a boy went to Haiti with his father, growing up in Port-au-Prince. As a youth he removed to Monte Cristi, where he established himself in business and took part in the War of the Restoration against the Spaniards. Having with Heureaux, he resided for a number of years in Cape Haitien, Haiti, and from there directed conspiracies against the dictator.

In May, 1898, Jimenez made a bold attempt to overthrow the Heureaux government. He fitted out a small steamer, the "Fanita," in the United States and left ostensibly to aid the Cuban insurgents; and as the United States was then at war with Spain the expedition was not opposed by the American government. A landing was made at Monte Cristi with only twenty-five men, a general uprising being expected as soon as his arrival became known. Jimenez' followers took the town, but the governor of the district was able to escape to the country and returned with a large force, driving Jimenez back to his vessel with a loss of one-half of his companions. The "Fanita" had touched in the Bahamas on the way down and on returning to Inagua Island, Jimenez was arrested by the British authorities as a filibuster. Heureaux sent a man-of-war to Nassau and did all he could to have the case pressed. Jimenez was tried twice; at the first trial the jury did not agree, and the second time he was acquitted.