"Mormon" is a nickname for members of the Church of Jesus Christ of Latter-day Saints. In the nineteenth century they were among the first white settlers of Utah, USA. As part of their religious practices, they abstain from drinking alcohol.
The mother of Mara Rogers, Sara Rogers Smithers, was adopted by Mormons following the deaths of her parents. In 1879, she joined a wagon trail of two hundred and fifty Mormons who settled in Bluff, bringing with her the alicorn and the Rogers family journal used to document it.