Thomas Horner was the eldest son of George Horner II (MM42) of Mells, Somerset and his wife Elizabeth Fortescue (1658–1693), daughter and co-heir of Colonel Robert Fortescue of Filleigh, Devon (MM38) and his second wife, Susanna Northcote. He was educated at Trinity College, Oxford, and in 1713 married Susanna (d. 1753), daughter of Thomas Strangways I of Melbury Sampford, Dorset. On the death of her brother, Thomas Strangways II, in 1726 Susanna inherited the Melbury estate and Thomas Horner took the family name; he was thereafter known as Thomas Strangways Horner. 

The present portrait was possibly commissioned soon after Thomas succeeded to the Mells estate and was conceived as a pendant to that of his father, George Horner (MM42), painted some ten to fifteen years earlier. The similarity in terms of their facial features may have been deliberate and intended to underline the son’s lineage, as well as his physical resemblance to his father. Since Thomas Strangways Horner did not pursue a military career, the full armour and helmet may refer to his position as Sheriff of Somerset, an office he held from 1711 to 1712. The head of the carved stone dog, partially visible at the lower left, is a reference to its presence as a supporter in Horner’s family crest and recalls the dog which also appears in the portrait of George Horner. Both portraits have previously been attributed to John Riley, who was one of the leading portrait painters in London in the 1680s and was appointed Principal Painter to the Crown (jointly with Godfrey Kneller) after the Revolution of 1688. However, Riley died in 1691, well before this portrait was painted, and the long, tied linen cravats worn by both sitters did not come into fashion until the early 1690s, decreasing the likelihood of George Horner’s portrait being from his hand either. They are more likely to have been painted by two different artists with varying painting styles and techniques. Oliver Millar, who viewed the present picture at Mells in 1994, dated it to around 1700, noting its similarity to the work of the Swedish-born artist Michael Dahl, whose male portraiture it certainly resembles in style and technique.¹