Henri de Tonti, soldier, was associated with René Robert Cavelier, Sieur de La Salle, in the fur trade and in exploration of the Great Lakes region and the Mississippi Valley. He is linked to Texas history through his search for La Salle's Gulf Coast colony. Tonti wrote an account of his 1689 expedition, which entered eastern Texas through the Caddoan tribes, recounting both the journey's hardships and his observations that bespoke great promise for the region. Tonti was born in 1649 or 1650, probably in Gaeta, Italy, the son of Lorenzo de Tonti and Isabelle di Lietto. Lorenzo de Tonti, a former governor of Gaeta and a financier of considerable note, invented a form of life insurance known as the tontine. Because of his involvement in an unsuccessful revolt against the Spanish viceroy in Naples, Lorenzo sought asylum in France. The family arrived in Paris about 1650—either shortly after or just prior to Henri's birth. Henri de Tonti entered the French army in 1668 as a cadet and later served in the French Navy. After losing his right hand in a grenade explosion at Labisso during the Sicilian wars, he substituted a metal hook, over which he customarily wore a glove, and thus became known as "Iron Hand." In July 1678 Tonti went with La Salle to Canada. La Salle, quickly recognizing that "his energy and address make him equal to anything," soon after his arrival was planning to send him to establish a fort near Niagara Falls. In March 1680 La Salle left Tonti to hold Fort Crèvecoeur (Illinois), while he himself returned to Fort Frontenac on Lake Ontario. In the spring of 1682 Tonti accompanied La Salle on his descent of the Mississippi River and explored one of the branches at its mouth. His letters and memoirs of this and other expeditions comprise a body of valuable source material on La Salle and Mississippi Valley exploration.
When La Salle sailed for France in 1683 to advance his plan for planting a colony on the lower Mississippi, Tonti was left in command of Fort Saint-Louis on the Illinois River. Early in 1686, after learning that La Salle had sailed from France to seek the Mississippi from the Gulf of Mexico, he voyaged down the river hoping to join him and support his undertaking. Failing to find La Salle, he searched the Gulf Coast twenty to thirty leagues in either direction, then returned to the mouth of the Arkansas River, where he left several men to establish a trading post. It was of this undertaking that Alonso De León heard through an Indian messenger following his 1689 Texas entrada and his discovery of the ruins of La Salle's fort on Garcitas Creek in the area of present-day Victoria County. During most of 1687 Tonti was involved in wars with the Iroquois and the English. In the spring of 1688 he returned to Fort Saint-Louis on the Illinois to find five members of La Salle's company-including La Salle's brother, Abbé Jean Cavelier-who had traveled from the Texas settlement. Abbé Cavelier, wishing to obtain a loan from his brother's account to pay for passage to France, concealed from Tonti the fact that La Salle already was dead. Had he revealed the truth, Tonti might have had time to rescue the twenty-five men, women, and children La Salle had left at La Salle's Texas Settlement. When he learned the truth ten months later, he had no way of knowing that it was too late to save those in the meager settlement on the Gulf. First sending Jean Couture among the East Texas Indians to seek news of any survivors, Tonti himself started for the Caddoan tribes in October 1689.
Traveling up the Red River by canoe, he reached the Kadohadacho villages near the northeastern corner of the present state of Texas in March 1690. It was of this journey that Alonso De Leon heard later that year while among the Hasinai, and of which Domingo Terán de los Ríos was told while encamped on the Colorado River in July 1691. From the Kadohadacho Tonti heard that seven Frenchmen remained among the Nabedache of the Hasinai confederacy, eighty leagues away. Deserted by most of his companions, he resumed his journey in April 1690. When he approached the Nabedache village, he learned of the Spanish expedition that was soon to establish San Francisco de los Tejas Mission among the Nabedache of the Hasinai confederacy. The Indians refused him guides to look for La Salle's remnants or to take him to La Salle's Texas Settlement, which he reckoned to be eighty leagues distant. With no course left open but to withdraw, Tonti returned eastward through flooded country, constantly facing starvation and losing the notes he had made during the journey. Despite such hardships Tonti saw great possibilities in the country he had visited for the harvest of peltry, silk production, lead mining, and a thriving commerce that would supply the Caribbean islands with lumber and agricultural products. Early in 1700 Tonti journeyed down the Mississippi to make contact with Pierre Le Moyne, Sieur d'Iberville, who the previous year had begun the Louisiana colony. Driven by the failure of his commercial enterprises in the north, Tonti eventually joined Iberville's colony and in 1702 was chosen by Iberville as Indian agent with the initial assignment of making peace between the Choctaw and the Chickasaw. Tonti continued to serve the colony under Iberville's brother, Jean-Baptiste Le Moyne de Bienville, in reconciling Indian nations and leading punitive expeditions. In August 1704 Tonti contracted yellow fever. He died at Fort Louis de la Louisiane (Old Mobile, twenty-six miles up the Mobile River from the present city) on September 4, 1704.