Astrology and the Book of Taliesin
The Book of Taliesin occupies an unusual place in Welsh literary history. It contains some of the oldest surviving Welsh poetry, preserves material associated with the sixth-century bard Taliesin, and also presents a later, almost mythic Taliesin: poet, seer and possessor of extraordinary knowledge.
That last aspect is where astrology enters the picture.
The surviving manuscript, Peniarth MS 2, was copied by a single scribe in the first half of the fourteenth century, although many of the poems it contains are substantially older. The National Library of Wales notes that the collection includes both praise poetry associated with the historical Taliesin and later works reflecting the learning that accumulated around his legendary persona. ([library.wales](https://www.library.wales/discover-learn/digital-exhibitions/manuscripts/the-middle-ages/book-of-taliesin))
Taliesin as Poet, Prophet and Reader of the Heavens
Modern scholarship provides surprisingly strong evidence that some of the poems associated with Taliesin understood celestial knowledge as a source of prophetic authority.
Mark Williams, in his Oxford University study Fiery Shapes: Celestial Portents and Astrology in Ireland and Wales 700–1700, argues that poems probably dating from the eleventh or twelfth centuries show an awareness of the occult significance of knowledge of the heavenly bodies. In these works, that knowledge helps establish Taliesin not merely as a poet but as a learned prophet. ([academic.oup.com](https://academic.oup.com/book/2801/chapter/143323609))
A particularly important word is sywedydd, which Williams notes can carry the sense of a sage, seer or astrologer. The implication is significant: understanding the heavens forms part of what makes Taliesin's knowledge extraordinary.
This does not mean that the Book of Taliesin contains natal charts, zodiacal delineations or a technical astrological manual. Rather, it preserves an older idea that knowledge of celestial phenomena could reveal truths inaccessible to ordinary observation.
Celestial Knowledge and Prophecy
In medieval Europe, the boundary between astronomy and astrology was considerably less rigid than it is today. Observing planetary movements, eclipses, comets and unusual celestial phenomena could have practical astronomical value while also carrying political or prophetic significance.
The Taliesin material appears within that broader intellectual world.
Williams identifies the Welsh poems as among the earliest literary appearances in Wales of an ideal he describes as prophecy from the heavens. Taliesin's authority partly rests upon his ability to comprehend the structure and signs of the cosmos. ([academic.oup.com](https://academic.oup.com/book/2801/chapter-abstract/143323609))
This is important because prophecy in the Taliesin tradition is not simply spontaneous supernatural vision. Knowledge itself matters. The inspired poet understands things other people do not: origins, histories, transformations and, at times, the workings of the heavens.
Not a Secret Celtic Zodiac
The strongest evidence is also more restrained than some modern interpretations suggest.
There is no reliable basis for claiming that the Book of Taliesin preserves a complete pre-Christian Welsh zodiac or an independent system equivalent to later Western horoscopic astrology. Claims of that kind tend to project modern reconstruction backwards onto medieval material.
The manuscript itself is a collection rather than a single work composed at one moment. The National Library of Wales dates the surviving codex to the first half of the fourteenth century and notes that its contents draw both upon native Welsh tradition and forms of learning derived from Latin sources. ([library.wales](https://www.library.wales/discover-learn/digital-exhibitions/manuscripts/the-middle-ages/book-of-taliesin))
That mixture is probably the key to understanding its celestial material. Taliesin sits at the meeting point of inherited Welsh ideas about poets and prophets and the increasingly sophisticated cosmological knowledge available in medieval Christian Europe.
Taliesin, Merlin and Astrological Prophecy
The connection becomes even clearer when Taliesin is considered alongside another famous prophetic figure: Merlin.
Geoffrey of Monmouth, writing during the twelfth century, depicted Merlin interpreting celestial portents in works such as the Historia Regum Britanniae and Vita Merlini. Williams argues that Geoffrey was drawing simultaneously on Welsh prophetic traditions and on the new astrological learning entering western Europe through translations of Arabic texts. ([academic.oup.com](https://academic.oup.com/book/2801/chapter/143323609))
Taliesin and Merlin therefore belong to a developing medieval image of the learned seer: someone whose authority derives partly from understanding the cosmos.
That does not make either figure an astrologer in precisely the sense understood by a modern natal astrologer. It does, however, show that astrology and celestial interpretation were becoming embedded within the literary language of prophecy.
A Wider Welsh Astrological Tradition
The association between Welsh learned culture and astrology did not end with Taliesin.
Later Welsh manuscripts preserve unequivocally technical material. One sixteenth-century National Library of Wales manuscript, Llanstephan MS 117, contains a planisphere, calendar, planetary tables and other astrological material alongside poetry attributed to Taliesin and other Welsh poets. ([archives.library.wales](https://archives.library.wales/index.php/miscellanea-133))
This manuscript is several centuries later than the Book of Taliesin, so it cannot be used to prove what the earlier poets believed. It does, however, demonstrate that astrology became part of the intellectual environment inhabited by later Welsh poets and manuscript compilers.
The relationship between poetry, prophecy and celestial knowledge therefore persisted rather than disappearing.
What Astrology Adds to Our Reading of Taliesin
For modern astrologers, the most valuable lesson may be less about reconstructing lost techniques and more about understanding how astrology once functioned culturally.
Celestial knowledge could signal wisdom. The person capable of reading the heavens possessed access to a larger order within which earthly events could be interpreted.
That conception fits the legendary Taliesin remarkably well. His poetry repeatedly presents knowledge as something expansive: knowledge of history, transformation, hidden things and the structure of existence itself.
At Wilfred Hazelwood Astrology, the Book of Taliesin therefore offers something more historically interesting than the idea of a forgotten "Celtic astrology". It shows us a medieval Welsh tradition in which the heavens, prophecy and poetic wisdom could genuinely belong to the same intellectual landscape.
The surviving evidence does not tell us that Taliesin cast horoscopes. It tells us something subtler: to imagine a truly extraordinary seer, medieval Welsh writers imagined someone who understood the sky.
