Gerard ter Borch, 'An Officer dictating a Letter', about 1655-8

How do we decode this enigmatic scene? The central figure is dressed in the fashionable clothes, breastplate and black felt hat of a military officer. He gestures, apparently dictating a letter to the man with the quill. He is wearing a breastplate and helmet, so must be a soldier on duty.

Meanwhile their comrade – in the impressive blue jerkin – seems more interested in us, and stares directly out of the painting. A seventeenth-century audience would have recognised his spurs, sword and the bugle hung over his back. It’s the costume of a military trumpeter who would have served as a cavalryman, sounding orders during battle, making proclamations and delivering messages. So in this context we must assume that he’s a messenger waiting for the scribe to finish writing. His faintly amused look and the way he catches our eye creates a conspiratorial air: there is something about the letter which he seems to want to share with us.

Ter Borch originally included a clear clue to what this might be but then changed his mind. Look on the floor just in front of the dog’s hind leg. After nearly 400 years the paint has faded to reveal a playing card laying face up on the boards. It’s the ace of hearts. This would have almost certainly been interpreted as a reference to romance, and a clear suggestion that it’s not a vital military message being drafted, but a love letter. Analysis shows that before, or just after, the painting was finished, ter Borch painted out the card, presumably to make the situation more enigmatic.

Comparisons with similar paintings by ter Borch and his studio suggest that he may also have made another change: adding the spaniel to the foreground. Like the trumpeter the dog meets our eye, though with a bored rather than a bemused look. That’s perhaps not surprising. The letter writing has apparently gone on so long that one broken clay pipe has already been discarded on the floor and parts of the stem have been crushed by the fidgeting boot of the scribe.

So without a certain amount of guesswork and a few assumptions, we can’t be absolutely sure what is going on – which seems to have been the effect ter Borch was seeking. He had begun his career in the 1630s as a painter of more traditional and rowdy guardroom scenes, but developed his own style of quieter, more reflective and enigmatic versions such as this one, often hinging on the writing or receiving of a mysterious letter.

This is not a portrait of ‘real’ people in a ‘real’ situations, however. Several elements of the composition appear in other paintings by him, including the dog (in A Woman playing a Lute to Two Men) and the young officer, which is most likely a portrait of Caspar Netscher, ter Borch’s most successful pupil.