The calendar on a stick

Runic calendars and primstavs: golden numbers, Sunday runes and saints' marks carved on wood and bone — the contraption you could hold. ← Calendar Contraptions

Before printed almanacs, northern Europe kept its calendar on a flat wooden staff, half a metre long and as wide as your hand. One line of runes counted the weeks, a second line of runes found the new moons, and a third recorded the feasts — carved once, good for ever. The Norwegian form is the primstav, the Swedish one the runstav; a few thousand survive. This page rebuilds one: pick a year and the staff is carved for you, with every machine it contains laid bare — including the place where its moon quietly goes wrong.

The year machine

The staff, carved for —

The golden line

The staff's second row is its moon machinery: a fixed sequence of marks, one per new moon of the 19-year cycle. Each mark carries the golden number of the cycle-year it belongs to — so to find this year's new moons, you slide a finger down the line and stop at every mark bearing this year's rune. The machine below is the whole line, rebuilt from the medieval rule: the epact of the year (11 days of moon-age per cycle-year), the first new moon, and then one moon every 30 and 29 days, alternating.

The stick for a day

The sky, and the stick's version of it

The primstav's merkedag table fixes four marks to the sky itself: spring equinox, summer solstice, autumn equinox, winter solstice. But the stick was a Julian-calendar object, and its marks were cut for a sky that has since moved on — pick a year and compare.

How to read a stick

To use a runstav you needed exactly two facts for the year, and both were published, taught and memorised: the year's golden number and its Sunday rune — what the Latin West called the dominical letter, wearing furs. The survival of so many staffs may be because the Swedish psalm books of 1545 and 1567 carried instructions for the reading; a 1690 handbook taught the whole thing to common people. Everything else on the staff is fixed forever: the 52 repetitions of the seven weekday runes (52 × 7 = 364 — the year's spare day or days fell outside the row and often got a mark of their own), the 235 marks of the golden line, and the saints and their symbols.

The moon that fits, almost

Nineteen tropical years last 6,939.602 days; 235 lunar months last 6,939.689. The gap is 2 hours 5 minutes 16 seconds per cycle — Meton of Athens spotted the fit in 432 BC, and it is still the best cheap trick in lunisolar timekeeping. The ecclesiastical books rounded the cycle to a crisp 6,940 days: 125 full months of 30 days and 110 deficient ones of 29. The staff's line is that count made visible — 235 marks, each golden number appearing twelve times, and seven of the nineteen getting a thirteenth (the seven years that carry an extra moon). But the two hours and five minutes are real, and a Julian calendar adds its own slow wander on top: on a carved stick the true crescent arrives a little earlier than its mark every cycle — a day in about three centuries, three to four days over a millennium, which is exactly what Swedish sources record. Carvers knew; from 1690 new staffs carried corrected golden numbers, the line shifted to catch up. As long as you knew your stick was drifting, it still worked; the moon on the stick was never the moon in the sky, and nobody had promised it was.

The three runes that had to be invented

The golden numbers needed nineteen symbols, but the Younger Futhark has sixteen runes. The last three golden numbers got runes of their own, improvised for the job: 17 is ᛮ árlaug, 18 is ᛯ tvímaðr ("two men"), and 19 is ᛰ belgþórr. They exist almost nowhere outside calendar sticks; Ole Worm, the Danish antiquary, wrote down their values in 1636. Later staffs stopped pretending and carved plain pentadic tally numerals 1–19 instead.

The primstav: saints, then farm work

The Norwegian stick mostly drops the runes. Days are plain notches; the feasts get small carved figures — an axe for Olsok, a key for Peter ("Peter with the golden key"), a rake for Kari med riva on 12 July, a bear's foot for Bjørnevåk, the bear's stirring. The name comes from Latin prima — the golden number itself, or prima luna, the first moon after the spring equinox — though golden numbers are rare on Norwegian sticks; after the saints' meaning faded in the Reformation, the marks slid into being farm reminders, and one scholar suggests messestav, the mass-day staff, was always the truer name. Around 650 survive in Norway, carved between the late 1400s and the early 1800s. The year is split in two halves: the summer face ran from 14 April to 13 October, the winter face from 14 October to 13 April — which puts the stick's own midsummer on 14 July and midwinter on 14 January, exactly half a face from each end. The two faces are still visible in Norwegian speech: the weather on vinterdagen, 14 October, was read as a forecast for the whole winter, and 28 October was fyrebod — firewood warning, winter is coming.

A family of sticks

The primstav is Norway's and Denmark's shape; Sweden carved runes instead, Denmark sometimes tally digits for the moon's phases, and Västergötland used its own cipher. Estonia kept the sirvikalender — thin boards tied together with a cord — and read the month as hard times (new, full and old moon: cut timber now, it will not rot) and soft times (the moon growing or shrinking: plant, clean, mend). The oldest surviving runstav is the Nyköping staff, dug up in 1964: octagonal, yew, from the mid-1200s, its golden runes still cut in late-eleventh-century forms. Two Norwegian-style staves from 1437 and 1457 sit in the National Museum of Denmark — the 1457 one is the oldest known primstav. The first book to mention runstav calendars was Olaus Magnus's 1555 Historia de gentibus septentrionalibus; the first printed runic-almanack tables, with Latin letters and plain Arabic numerals instead of runes, had already appeared in the Breviarium Scarense of 1498.

What killed the stick

Two reforms and one piece of paper. Denmark–Norway joined the Gregorian calendar in 1700 (ten days vanished — see Ten days that never happened), and printed almanacs got cheap; the primstav faded from there, though Setesdal farms still used one into the 1800s. Sweden switched in 1753, and that was that for the runstav: its Sunday runes and golden numbers were built for the Julian calendar, and the reform made the old sticks unusable overnight. A few were re-carved for the new calendar; most became heirlooms, walking sticks for antiquarians, and — in the Nyköping staff's case, long before anyone knew what it was — a tool for measuring timber.

Honest limits

The moon on this page is the staff's moon — arithmetic, not astronomy. It places one new moon every 30 and 29 days, alternating, anchored by the medieval epact rule; its mean month over the cycle is 29.532 days against the real 29.53059, and the true crescent pulls ahead of the fixed marks by about a day every three centuries. The line also cannot see the leap day: after a bissextile February its marks run a day behind the sky for the rest of the year, because the carved staff has nowhere to put February 29. The weekday-rune reading (ᚠ as A through ᚼ as G, and the choice to run the row from 1 January) is this page's convention, stated plainly: surviving staffs differ in their assignments, and the reading skill — Sunday rune plus golden number — is what the sources agree on. If the runes above show as empty boxes, your device lacks a runic font; every rune here also carries its name in plain letters. The solstice comparison uses UTC dates, and the merkedag table is the Norwegian tradition as recorded on Primstav (Norwegian Wikipedia) — sticks varied from valley to valley, and the same day could carry different marks in different parishes.