24 Mackenzie’s Voyages of the X.Y. Company and the North-Westers, and, after the amalgamation, Alexander Mackenzie was sent to take charge of the important department of Athabasca. In 1788 Alexander wrote to his cousin Roderick divulging his intention to undertake a voyage of discovery the next year down the river that runs out of Slave Lake to the Northern Ocean. In order to further this plan he begged his cousin not to retire as he had intended, but to accompany him to Athabasca to take charge of that district, and thus enable the prospective explorer to carry out his project; above all he was not to mention this matter to anyone, as a knowledge of his proposed expedition might affect his standing with the powerful interests at Montreal. Alexander was so earnest in his appeal that Roderick felt moved to accede to his request and accompanied him to the new district. The new chief thought at first of abandoning the posts farther north and withdrawing from the district, but, on more mature reflection, decided not only to retain all of them but to establish others. He therefore sent Boyer to establish a post on Peace River, and Le Roux was directed to go back to Slave Lake to the post already built there, and another was begun at Lac a la Martre, fifteen days’ travel from Great Slave Lake towards the north-west. Roderick was commissioned to select a site for a new establishment on Lake Athabasca, where, after a careful inspection, he decided upon a location on a promontory, on the south side of the lake, eight miles east of the mouth of the Athabasca River. The fishing was good, a very important matter for these northern posts which had to depend largely on fish for their food supplies. Roderick Mackenzie was entrusted with the task of building the fort, and made such a good job of it, that the astronomer Turner, David ‘Thompson, Simon Fraser, and