The Cnóbha Celtic Ogham Calendar is a lunisolar reconstruction rooted in Celtic tradition. Like the Anglo-Saxon and Norse calendars, it is based on the 19-year Metonic cycle, aligning the solar year with the lunar months.
Rather than drawing from Anglo-Saxon or Norse cosmology, this calendar is inspired by the cultures of the Romano-Gaulish and Irish Celts.
This system is a reconstruction. While no surviving evidence shows that Ogham was historically used in calendar systems, this design explores how it could have functioned if applied in a way similar to the runic calendars of northern Europe.
Sources and Inspiration
The calendar brings together several historical layers:
Ogham Script — an early Irish writing system, traditionally carved vertically.
Coligny Calendar — a 2nd-century bronze calendar from Roman Gaul, providing the month names and structure.
Knowth (Cnóbha) — a Neolithic site (c. 3200 BC), whose carved glyphs form the outer border.
Lindisfarne Gospels —Influencing the visual ornament and layout, and is an illuminated manuscript gospel book, produced probably around the years 715–720, in the monastery at Lindisfarne, off the coast of Northumberland.
The names around the border include:
- The four cross-quarter festivals preserved in early Irish tradition
- Reconstructed Welsh names for the solstices and equinoxes
Together, these elements create a calendar that bridges prehistoric symbolism, Celtic language, and later manuscript tradition.
How It Works
Step 1 — Determine the Year
Start with the Gregorian date.
Example: March 1, 2026
- Divide the year by 19
- Take the remainder
- Add 1
2026 ÷ 19 = remainder 12
12 + 1 = 13
This places the date in Year 13 of the Metonic cycle.
On the calendar:
- Find March 1 on the inner Gregorian ring
- Move outward through the rings
- Stop at the 13th ring
This corresponds to the Ogham year:
Ngetal
Step 2 — Determine the Month
The calendar uses month names from the Coligny system.
For March 1, 2026 (Year Ngetal), the month is:
Anagantios
These names come from Gaulish tradition and reflect a lunisolar structure that predates the runic calendars by several centuries.
Step 3 — Determine the Lunar Phase
Each month begins on a new moon.
By locating your position within the month:
- Beginning → new moon
- Middle → full moon
March 1 falls in the second half of Anagantios, placing it in a:
Waxing gibbous phase (approaching full moon)
Step 4 — Determine the Weekday
The weekday system follows the same underlying principle as the other calendars:
- A repeating 7-day cycle
- Represented symbolically rather than by modern weekday names
By tracing your date across to the weekday ring, you can identify the day within that cycle.
Step 5 — Find Seasonal and Ritual Context
The outer ring connects each date to seasonal and ceremonial markers.
These include:
- Cross-quarter festivals (such as Imbolc, Beltane, Lughnasadh, Samhain)
- Solstices and equinoxes
- Broader seasonal transitions
This reflects a way of tracking time grounded in:
- Land
- Light
- Seasonal change
Final Understanding
Using the calendar reveals multiple layers of time at once:
- Solar (Gregorian date)
- Lunar (moon phase)
- Seasonal (Celtic months and festivals)
- Symbolic (Ogham script)
This calendar is not a direct historical artifact, but a living reconstruction—a way of exploring how Celtic systems of language, landscape, and time might be brought back into alignment.
The Galdorcraft Celtic Ogham Calendar is a perpetual calendar built from the lunar, seasonal, agricultural, and festival cycles of the Celtic world.
It is designed to help you reckon the year through circles and cycles rather than boxes and rows.
The calendar brings together:
• The traditional Celtic months
• The movement of the moon through the year
• The seasonal quarter days and cross-quarter festivals
• Agricultural and natural markers
• Ogham symbolism
• The wider cycle of the year
This is not a calendar for one single year.
It is a perpetual calendar that can be used year after year as a guide to the repeating movements of moon, season, festival, and land.
The design was developed through research into Celtic calendars, Ogham traditions, medieval feast days, agricultural customs, seasonal folklore, and surviving systems of traditional timekeeping.
