Why medieval glass worked like a picture book

Before printed Bibles and widespread literacy, the parish church window did the teaching. A congregation that could not read a Latin psalter could still recognise a halo, a key or a wheel. Glass was also expensive, so patrons — guilds, merchants, lords and the clergy — chose their subjects carefully. Each window was commissioned with a job to do: to honour a patron saint, to remind the viewer of judgement, or to advertise the donors' piety and their trade.

That is worth remembering when you are standing in a nave. Not every figure is a saint. Some are kings, bishops, angels, or donors kneeling in prayer. Some panels are heraldry, some are fragments. Reading a window is partly deduction: what is the figure holding, who stands beside them, and what is written on the scroll above?

Look before you interpret

Binoculars help more than any guidebook. So does timing. Stained glass is backlit, so a north window on a bright day is easier to see than a south window with the sun behind it. Morning light flatters east windows above the altar; afternoon light is better for west windows.

Start with the composition, not the detail. Is the window one large figure, a row of separate lights, or a grid of small medallions? Medieval glaziers often arranged narratives to be read from the bottom upwards, panel by panel, because the glass was set in horizontal bands. Look at the lead lines — the strips of lead, called came, between pieces of glass. A neat medieval grid suggests original work; a patchwork of odd shapes may be a window re-leaded after Reformation iconoclasm or Civil War damage, with the surviving panels shuffled together.

Saints and their attributes

Saints are identified by the object they carry — their attribute. Learn a dozen and you can name most figures in an English church.

• St Peter — keys, often with a cockerel nearby.
• St Paul — a sword and a long beard.
• St Catherine of Alexandria — a spiked wheel, sometimes broken, and a book.
• St Margaret of Antioch — a dragon at her feet, or emerging from one.
• St Michael — scales for weighing souls, sometimes a spear.
• St George — a red cross on white, a dragon, a broken lance.
• St John the Baptist — a lamb resting on a book, and a rough camel-hair garment.
• St Nicholas — three gold balls, or three boys in a tub.
• St Anne — frequently shown teaching the young Virgin Mary to read.

Where a figure carries nothing recognisable, look at the scroll or the inscription beneath. It may name them in Latin — Sanctus Petrus — or in English on later glass.

Biblical figures and the art of pairing

Medieval designers loved typology: the idea that events in the Old Testament prefigured events in the New. A window may deliberately place two scenes side by side so the viewer draws the parallel. Jonah emerging from the whale stands for the Resurrection. Moses striking the rock prefigures the water from Christ's side. Abraham's near-sacrifice of Isaac foreshadows the Crucifixion.

The grandest version is the Jesse Tree, a vine climbing from the sleeping body of Jesse, father of David, with the kings of Judah in the branches and the Virgin and Christ at the summit. It was a favourite from the twelfth century onwards and appears in cathedrals and parish churches alike.

Seasonal and calendar motifs

Some subjects follow the Church's year: the Annunciation, the Nativity, the Passion, the Resurrection and the Ascension. Others follow the calendar of daily life. The Seven Corporal Works of Mercy — feeding the hungry, clothing the naked, visiting prisoners — were popular in the fifteenth century because they gave the viewer something to do as well as believe. The Dance of Death and the Wheel of Fortune remind the onlooker that status is temporary. A skull, a corpse or an hourglass is a memento mori, a nudge to consider mortality.

Look too for the Doom, a Last Judgement glazed or painted above the chancel arch, and for small background details: ploughing, harvesting, fishing, a mill, a ship. These are the labours of the months, and they anchor the sacred story in the working year of the parish.

Colour, glass and a few cautions

Colour itself carries information. Silver stain, a yellow that could be painted onto glass and fired, came into use around 1300, so plenty of yellow alongside blue suggests later medieval work. Deep ruby and rich blue were costly; much medieval glazing was actually grisaille — pale greenish-white glass with delicate foliage and only limited colour, not a rainbow. If a window looks very smooth, sentimental and crisply drawn, it is often Victorian or early twentieth-century work imitating the medieval manner.

Finally, do not over-read. Glass breaks, gets moved, gets restored. A mismatched panel may be a medieval fragment in a Victorian setting, or a donor's portrait inserted centuries later. Take a photograph, compare it with the church guide, and ask a steward. Reading a window is a slow pleasure, best done on a dull afternoon with a pair of binoculars and no hurry at all.