Sarah Mallet (1764-1846) was one of the very small group of women authorised by John Wesley to become a preacher, in the early days of Methodism.
After Wesley's death, she married, and as Sarah Boyce, she continued to preach for another forty years - despite the ban on female preaching, imposed by the Wesleyan Methodist Church in 1803.
Further details are available in her biography, 'My Dear Sally' by David East (published by World Methodist Historical Society Publications in May 2003).