Context
Winter, 1811. David Thompson was crossing the Rocky Mountains. He was a surveyor, trader and mapmaker for the North West Company, and his Iroquois guide, Thomas, was showing him the route. On 4 January his party of twelve trudged along the frozen Athabasca River, hauling pemmican, grease, flour and half-dried meat. Behind them, at Henry House near present-day Jasper, William Henry kept the supplies and horses.