Through Thick and Thin

The popular story

Most people meet ‘through thick and thin’ as a pure figure of speech – a way of saying someone stuck around through good times and bad, thick standing loosely for prosperity and thin for hardship. It gets attached to marriages, friendships and football clubs, and the assumption is that it was always an abstract metaphor.

What the record shows

The written record is older and far more concrete. The Oxford English Dictionary traces the phrase to Geoffrey Chaucer’s ‘The Reeve’s Tale’, one of the Canterbury Tales composed around 1387–1400. When a miller sets loose two students’ horse, the animal bolts:

And whan the hors was laus, he gynneth gon / Toward the fen, ther wilde mares renne, / And forth with “wehee,” thurgh thikke and thurgh thenne.

Here the sense is literal terrain. A fen is a marsh, and ‘thikke’ and ‘thenne’ describe the horse crashing through dense cover and thinner, more open ground on its way to the wild mares. In an England that was still heavily wooded, moving ‘through thick and thin’ was a vivid, everyday picture of pressing on regardless of what lay underfoot.

The verdict

Attested. The first appearance is real, datable and reputably sourced: Chaucer, c.1387, flagged by the OED as the earliest known use. The origin is genuinely woodland-and-terrain, not a later invention. The literal-to-figurative shift is exactly the kind of drift you would expect, and the modern spelling is itself documented – Richard Baxter’s A Saint or a Brute uses ‘through thick and thin’ in 1662.

What we don’t know

The neat gloss that the phrase is short for ‘through thicket and thin wood’ should be handled with care. It is a reasonable reconstruction of the image, and it is repeated by good reference sites, but ‘thicket and thin wood’ is not itself an attested earlier form – Chaucer wrote ‘thikke’ and ‘thenne’. We also cannot fix Chaucer’s exact year: the Canterbury Tales are dated to a span (roughly 1387–1400), so any single year, including 1386 or 1387, is an approximation of when this tale was written.

How it changed

Over the 15th to 17th centuries the phrase loosened from describing physical travel to describing steadfastness through any kind of difficulty. By the time Baxter used it in 1662, the wording had settled into the modern ‘through thick and thin’ and the meaning was firmly figurative: carrying on, or staying loyal, whatever the obstacles.

Usage today

Today it is almost always about loyalty and endurance – a person, cause or relationship you stick with no matter what. Example: ‘She stood by him through thick and thin, from the bankruptcy to the long recovery that followed.’ The galloping medieval horse is long gone, but the underlying image of pushing forward through hard going and easy alike is still doing the work.