Kashan sits in north-central Iran, the seat of Kashan County in the northern part of Isfahan Province, on the western rim of the Dasht-e Kavir salt desert and on the old road between Tehran and Isfahan, roughly midway between the two. It is an oasis city and one of the country's oldest continuously inhabited places, with the prehistoric mounds of Sialk on its south-western edge. Long before carpets, Kashan was known for silk cloth, for rosewater distilled at nearby Qamsar, and for glazed tilework so closely identified with the city that the Persian word for such a tile, kashi, comes from its name.

Rug weaving here is traced to the Safavid dynastySee in the carpet dictionary, in the sixteenth and seventeenth centuries. The Safavid rulers treated Kashan as a holiday retreat, and the large summer houses they built there were furnished to match: carpets were woven locally for the royal household, in the same court taste that governed the architecture and tilework around them. Kashan is named alongside Tabriz, HeratSee in the carpet dictionary and Kerman among the great production centres of that dynasty, the period whose surviving carpets now sit in museums and at the top end of the auction rooms.

That first golden age did not run unbroken. Production faded after the Safavid collapse, and the modern Kashan industry was re-founded late in the nineteenth century, during the revival when Persian weaving reached a commercial peak and exports to Europe and America grew quickly. This matters for what a buyer sees today. City workshop rugs of that revival were woven to a drawn cartoon rather than from the weaver's own memory, so their designs are standardised and immediately recognisable, in contrast to village and tribal weaving, where the weaver at the loomSee in the carpet dictionary was also the designer.

WoolSee in the carpet dictionary is the defining material, and the best of it never grew in Iran at all. Kashan pileSee in the carpet dictionary is ordinarily one hundred per cent wool, and the revival workshops worked in merino yarn imported through Manchester; pieces woven from it are still known in the trade as Manchester Kashans, and that wool is named alongside New Zealand and Ghazni fleece whenever the grades are ranked. It takes dye cleanly, holds a soft lustre and wears well under a lifetime of use. The foundation beneath it is normally cotton, which stays stable, holds the rug flat and resists the stretching that a finely drawn pattern cannot tolerate.

Design is where Kashan is deliberately narrow. Compared with Tabriz, which will weave almost anything, Kashan keeps to a small and very traditional repertoire: a central medallionSee in the carpet dictionary on an open field; the medallion-and-corner layout, in which the four corner piecesSee in the carpet dictionary usually repeat the colour of the medallion; the Shah AbbasiSee in the carpet dictionary floral; and the all-over floral, which covers the whole ground in a repeating pattern with no medallion at all. All of it is curvilinear and floral rather than geometric, drawn in flowing arabesques, palmettes, vines and sprays of blossom.

Shah Abbasi takes its name from Shah Abbas and began as a style of the court. Its two signature elements are the stylised palmetteSee in the carpet dictionary and the lotus, an ancient symbol of long life, arranged around a central medallion in strict symmetry, so that whatever appears on one side of the axis appears again, exactly, on the other. The medallion itself is generally read as a lotus, a flower with sacred weight in Persian carpet culture, and the field around it as a garden, an idea Persian weaving returns to again and again.

One rare layout is worth knowing. The darbari, meaning of the court and said to have been woven for kings, dispenses with the border almost entirely, so the field runs out to the edge instead of being framed. More useful to most buyers is a quieter rule: the smaller Kashans, around 150 by 210 centimetres and under, carry far more design variety than the big formal pieces. That is where you find the tree of lifeSee in the carpet dictionary, which stands for the bond between people and the living world, vase designs read as symbols of abundance, and fields filled with birds.

Three colours dominate: deep red, navy blue and cream. Highlights range wider, through lighter blues, beige, orange and yellow, and Kashan counts among the brighter Persian weaves, with Tabriz, Mashhad and Nain. Fields of yellow or green exist but are genuinely rare. The combination most associated with the city is an ivory or cream ground carrying dense floral work, framed by a border in deep jewel tones; the light centre gives an airy grace that a dark field cannot, and it is the look most people picture when they picture a Kashan. Newer weaving tends towards softer, more pastel colouring.

Knots are tied in the asymmetric, or Persian, form. DensitySee in the carpet dictionary is where expectations often run ahead of reality: fine antique Kashans measure roughly 240 to 330 knots per square inchSee in the carpet dictionary, with recorded examples at 240, 256 and 324. That is high by general standards and entirely sufficient for the curvilinear drawing the style depends on, but it sits below the extreme fineness of QumSee in the carpet dictionary, Isfahan or Nain, where a silk piece can run two or three times denser. Exceptional silk Kashans go finer than that band, yet a wool Kashan quoted at five hundred knots deserves a second look. Density alone has never been the measure of a good rug; the drawing, the wool and the dyes matter more.

Pile height is medium, in the same bracket as Tabriz, with enough body to wear for generations and enough restraint to keep the fine floral drawing legible. Formats run very wide, from small pieces that suit an entrance hall, a reading corner or the floor beneath a desk, up to palace carpets of about four by six metres made to fill a formal room; Kashan is one of a handful of Persian weaves that holds its knot density at that scale. The labour is easier to grasp in days: a fine 150 by 210 piece works out at roughly 160 weaver-days, a palace carpet at something nearer 1,700.

Signatures are worth looking for. A number of workshops built reputations in the city, and a woven signature in the field or near an end marks a piece that came from one of them rather than from an anonymous loom. MohtashamSee in the carpet dictionary, the master weaver of the late nineteenth-century revival, is the name that carries most weight, and the refinement it stands for is visible in the drawing itself, in how a petal is shaped and how a vine turns, rather than in the inscription alone. A signed rug is not automatically the better rug, but it is traceable, and that has always counted for something.

Age suits these carpets. Kashans of a century and more turn up regularly in excellent condition, still reading as clearly as when they left the loom, which says a good deal about the wool and the weave. Older colours look subtle rather than loud, the natural dyes having settled into one another, and the pile grows supple with decades of use. Silk-and-wool Kashans belong mainly to that older generation and usually sit on a silk foundationSee in the carpet dictionary; silk is chosen there for fineness, not for strength, so such a rug wants gentler placement than a wool pile on cotton.

A Persian rug is an Iranian rug — a rug hand-knottedSee in the carpet dictionary in Iran — and the tradition behind it is the oldest documented anywhere. The earliest surviving carpet, the Pazyryk rugSee in the carpet dictionary, was found preserved in a frozen burial mound and dates to the fifth century BC — roughly 2,500 years ago — and it is already accomplished work, not a beginner's craft. What began as warm, hard-wearing floor coverings for tribal households grew, over those centuries, into the art form that every other rug-weaving country has borrowed from.

Two later chapters shaped what a Persian carpet looks like today. Under the Safavid dynastySee in the carpet dictionary, from 1501 to 1732, the court promoted weaving alongside painting and calligraphy, and the workshops of Tabriz, HeratSee in the carpet dictionary, Kashan and Kerman produced the masterpieces that now sit in museums. This is when the great central medallionSee in the carpet dictionary appeared, and when designs grew elaborate enough that a separate designer — often a miniature painter — drew the pattern onto a cartoon for the weaver to follow. The second chapter came in the nineteenth century, under the Qajar dynastySee in the carpet dictionary, when production reached its historical peak, exports to Europe and America boomed, and the workshop industry whose descendants still weave today took its modern shape.

The trade sorts Persian rugs into three families. City rugs — Tabriz, Kashan, Kerman, Nain, Isfahan — are woven in workshops from a drawn design, carry the highest knot densities and come in the widest range of colours, sizes and patterns. Village rugs such as HerizSee in the carpet dictionary, BakhtiariSee in the carpet dictionary and KarajaSee in the carpet dictionary sit in between, mostly geometric and largely woven from memory. Tribal rugs — Baluch, TurkomanSee in the carpet dictionary, QashqaiSee in the carpet dictionary, each named after the people who weave it — are made on small portable looms, so they run smaller, and their bold geometric drawing comes from the weaver's own head rather than from paper.

The design vocabulary draws on a deep stock of motifs: Shah AbbasiSee in the carpet dictionary palmettes, flowing arabesques, the small repeating Herati patternSee in the carpet dictionary, medallions, garden and tree-of-life compositions. These combine with regional habits into styles a practised eye can place at a glance, from the bold geometric medallions of Heriz to the fine curvilinear florals of Isfahan.

The classic palette is built on natural dyes: madderSee in the carpet dictionary reds, indigo blues, saffron yellows and the soft whites of undyed woolSee in the carpet dictionary, settled into combinations refined over centuries. Natural dyes age gracefully, mellowing into the patina that older rugs are prized for, and slight shifts of tone between dye batchesSee in the carpet dictionary — the effect called abrashSee in the carpet dictionary — are a mark of small-batch natural dyeing, not a flaw.

The pileSee in the carpet dictionary is almost always woolSee in the carpet dictionary, and in a Persian wool rug the wool itself decides much of the quality. The best fleece comes from high-altitude flocks, where it grows thicker and richer in natural oils; spring-sheared wool beats the autumn clip, and hand-spun yarnSee in the carpet dictionary gives a finer, softer thread than machine spinning. Fine pieces add silk highlights to a wool pile, and at the very top sits the Persian silk rug, woven in pure silk. Foundations are usually cotton in city weaving, wool in tribal and older pieces, silk at the very top of the range.

Every knot is tied by hand, one at a time, in one of two forms: the asymmetric Persian knotSee in the carpet dictionary, usual in central and eastern Iran, or the symmetric Turkish knotSee in the carpet dictionary, common in the north-west ever since Seljuk weavers introduced it in the eleventh and twelfth centuries. A large rug holds in the region of two million knots and can occupy a weaver for about a year.

Knot densitySee in the carpet dictionary is the figure newcomers fixate on, and the finest silk-foundation pieces do reach as much as 1,000 knots per square inch. But densitySee in the carpet dictionary only matters as far as the drawing demands it: a curvilinear Isfahan needs a fine weave to stay sharp, while a geometric Heriz is famously durable at a modest count. Material, symmetry, colour harmony and condition say more about quality than any single number.

Persian carpets settle into modern rooms as naturally as classical ones, as a focal point in a living room, a foundation under a dining table or a quieter accent in a bedroom. Care is undemanding: gentle vacuuming without a rotating brush, an occasional turn for even wear, and a professional wash about every five years — sooner in a hallway or entrance, less often in a quiet room.

A hand-knotted Persian rug tends to outlast its owners. Pieces a century old regularly survive in fine condition, their colours settled and their pile supple, often looking better than when they left the loomSee in the carpet dictionary. A well-chosen, well-kept rug holds its worth and passes down as a family heirloom rather than being replaced — which is precisely what the knots, the wool and the dyes were always for.