Background
Pierre-Gabriel Marest was a native of Laval, where he was baptized in the old Gothic cathedral, seat of the bishop's see. The family was a religious one and two sons entered the Jesuit order, Gabriel and Joseph, both to become missionaries in Canada.
Education
Gabriel entered his novitiate October 1, 1681, at Paris, studied there and at Bourges, was instructor at Vannes, and in 1694, then thirty-two years old, was ordered to New France.
Career
When he arrived at Quebec, Iberville was just setting out on a buccaneering expedition to Hudson Bay and Marest was detailed as chaplain for the expedition, because, as he wrote, he knew no Indian language and could be better employed ministering to Canadians than to aborigines. Marest has given a thrilling account of his experiences in Hudson Bay, of the cold and storms, of the attack on the English fort and its surrender, of the Indians who visited the post, of the death in his arms of the commander's young brother Chateauguay, and of the final departure of Iberville's fleet in September 1695, leaving Marest to minister to the men of the French garrison. Not long after the vessels had gone, an English fleet swooped down on the post and carried the captured garrison off to England. There Marest experienced prison fare, but was shortly permitted to return to France, whence at the earliest opportunity he again set sail for Canada. In 1698 he embarked on another long journey, this time to the interior of America, where Father Jacques Gravier needed reinforcement in the Illinois mission. Marest ministered to the Kaskaskia branch of the Illinois tribe, at first located on the upper Illinois River near the present Ottawa. In 1700 the Kaskaskia determined to remove to the Mississippi, having heard that a French colony had been founded near the mouth of that great river. Marest, learning that his old leader Iberville was the founder of the colony, did not discourage his neophytes' removal. They spent the first years on the west side of the stream at the Rivière des Pères, now a part of the city of St. Louis, then, in April 1703, they crossed to the east side and formed a village on a river called for them the Kaskaskia. At this mission Marest passed the remainder of his life, except for a journey to Mackinac to consult with his Jesuit brother Joseph, whom he opportunely met en route at the St. Joseph mission. On his return he promised the Peoria to continue their mission; but his Kaskaskia converts and his colleagues would not consent to his removal. His mission was one of the most successful in North America; in 1707 he estimated that all the Kaskaskia, numbering over two thousand, were Christians. He was buried in the chapel of his mission of the Immaculate Conception; but on December 18, 1727, his remains were removed to the new church just finished at Kaskaskia.
Personality
He is said to have been an accomplished Indian linguist, but none of his manuscripts has survived. His letters are well composed, artless, and sincere.