William Roos, born in Amlwch, was a nineteenth-century artist who achieved some success travelling around Wales and beyond, painting mostly portraits. With the rise of the middle class, and more people eager to spend their money on the arts, itinerant painters like Roos were able to sustain a career by moving from town to town, pitching their wares then moving on. He relied almost exclusively on the support of Welsh patrons. Christmas Evans – so-called because he was born on Christmas day, 1766 – was one of the most powerful Welsh nonconformist preachers of his day. A fire-and-brimstone revivalist, he was famed for driving congregations to terror or religious ecstasy, and delivered his sermons with intense drama and humour. Roos’s painting captures the sheer physical power of the man – who was, reputedly, 7 feet tall, and had only one eye, the other blind socket being sewn shut. Roos first painted Christmas Evans in his home in 1835 – they were living next door to one another – and disseminated the image in a mezzotint engraving. An inscription on the painting describes him as ‘The most ideal Preacher Wales ever produced.’