Born in Marlborough, England, on the 4th of April 1809, died in Grahamstown on the 16th of August 1882. Educated at Marlborough, at Winchester College and Oxford (where he formed a lifelong friendship with W. E. Gladstone), Merriman was appointed curate of Street (Somersetshire) in 1840. In 3847 he offered his services to Bishop Gray and was appointed the first archdeacon of Grahamstown, with the task of supervising the Anglican Church in the entire eastern region of the Cape Colony.
Arriving at the Cape in November 1848, he and his wife and family reached Grahamstown early in 1849, and in February Merriman undertook the first of a series of visitation journeys, chiefly on foot. These are vividly described in his private journals, published without his knowledge in 1853 under the title The Kafir, the Hottentot and the frontier farmer. Never a seeker after office, Merriman finally accepted in 1870 the deanery of Cape Town and in 1871 was elected bishop of Grahamstown.
A year later he was elected to succeed Archbishop Gray but declined. He died as the result of a carriage accident near Grahamstown on 16 August 1882.
Unconventional and a man of great integrity, Merriman had a natural gift for observation, a remarkably objective approach to life at the Cape, and a refreshing sense of humour. He married Julia Potter in 1840. Their eldest son, John Xavier, became prime minister of the Cape and one of the architects of Union in 1910.