David Carnegie Andrew Agnew, Protestant Exiles from France… (1886)
“ In or about 1685 refugees from Saumur came to London, named Le Mercier. In 1691 Martha, daughter of René Bertheau, D.D., and sister of Rev. Charles Bertheau, was married in London to Lieutenant Claude Mercier, and left a son. There were Huguenot refugees of the name in Prussia, and one of the family removed to England — viz., Philip Mercier, born at Berlin in 1689, a painter praised by Horace Walpole, his departments of the art being portraits, and interiors of houses. ”
