Chosen by Joseph Smith as one of the first Mormon apostles, Parley P. Pratt endured imprisonment, persecution in Missouri, the trials of the exodus from Nauvoo, and the challenges of settling the Great Basin area. He became a significant thinker and writer of his time and culture. His wife, Thankful, and seven children preceded him in death; one wife divorced him; but he was survived by ten wives and twenty-two children.
In the winter of 1847, he sailed Utah Lake and explored Utah Valley, then went westward by horseback into Cedar and Tooele valleys, coming back into the Salt Lake Valley between the Great Salt Lake and the Oquirrh Mountains.
A general convention in March 1848 chose Pratt as one of ten to draft the first constitution of the provisional state of Deseret. In the summer of 1848, Pratt explored Big Kanyon Creek, now Parleys, for the purpose of building a road to provide easier access into the valley. In July 1849 his crops failed and he began making the road.