A detail from Bald's Leechbook, showing medical recipes in Old English.

Science and the natural world in Anglo-Saxon England

If you were studying science and technology in Anglo-Saxon England, your experience would be rather different from what you might expect today…

The Anglo-Saxons had a very developed knowledge of science and the natural world. They read treatises by earlier Greek and Roman writers and, in some cases, they formulated new theories and inventions to understand everything from astronomy to medicine to the tides of the sea.

Although our sources are limited, it is clear that this period was far from being ignorant and unsophisticated.

What was the place of science in Anglo-Saxon England?

The Anglo-Saxons did not approach scientific study in the same way that we do today. Medieval science was a branch of scholarship that complemented all other studies. One diagram shows how knowledge (phylosophyae) was divided at this time into different branches. It lists theology (the study of God), physics and mathematics as theoretical subjects, for abstract contemplation, while arithmetic, astronomy and music were identified as ‘practical subjects’.

Early medieval writers combined their knowledge of different subjects to understand the world around them. Byrhtferth, a monk and teacher at the abbey of Ramsey in the late 10th and early 11th century, devised a diagram that showed the universe as an inter-connected unit, full of repeating patterns, from the four winds to the four writers of the gospels.

Computus collection including Byrhtferth of Ramsey's diagram

A page from a 12th-century computus collection, featuring an annotated diagram by Byrhtferth of Ramsey.

The universe as an inter-connected unit; the inner circle contains the first letters of the Greek language terms for east (anathole), west (disis), north (arcton) and south (mesembrios), which as an acronym, spells out 'Adam' (British Library, Harley MS 3667, f. 8r)

View images from this item  (8)

Usage terms

Public Domain in most countries other than the UK.

Likewise, the book-list of a 10th-century scholar reveals that he owned books about grammar and poetry, in addition to a copy of De natura rerum (On the Nature of Things) by Isidore of Seville (died 636), a text that discussed astronomy, geography and medicine.

The Anglo-Saxons learned about the natural sciences in part through observation and by reading the works of earlier writers. Authors whose works were known to the Anglo-Saxons included the Roman scholar Pliny the Elder (died AD 79), the ancient Greek writer Aratus (died 240 BC), the 5th-century commentator Macrobius, and Isidore of Seville.

A world map made in 11th-century England was possibly based on Roman models and descriptions by earlier Latin writers.

Anglo-Saxon Mappa Mundi

A map of the world from an 11th-century Anglo-Saxon miscellany, containing the earliest known, relatively realistic depiction of the British Isles, seen in the bottom left hand corner

This map of the world was probably created at Canterbury in about 1025. Like other medieval world maps, it is orientated with east at the top (British Library, Cotton Tiberius B V/1, f. 56v)

View images from this item  (1)

Usage terms Public Domain

Anglo-Saxon inventions and discoveries

Some Anglo-Saxon writers made significant contributions to scientific knowledge. The Northumbrian monk Bede (died 735) made detailed records of the movement of tides, while the accounts of explorers such as Wulfstan and Ohthere, who travelled around the Baltic Sea and Scandinavia, were recorded in Old English manuscripts.

At the same time, the Anglo-Saxons’ knowledge of geography was naturally limited. This gave rise to speculation about the creatures and monstrous races that lived in faraway lands. One extraordinary text that circulated at this time was the Marvels of the East, which described dragons, gold-digging ants and headless men with their faces in their torsos (known as ‘blemmyae’).

Marvels of the East

A page from the Beowulf Manuscript, featuring the Marvels of the East, with illustrations of a blemmya, two snakes, and a centaur or homodubius.

The Marvels of the East is a fantastical account of the lands beyond Europe. This version appears in the same manuscript that also contains the Anglo-Saxon epic poem, Beowulf.

View images from this item  (10)

Usage terms

Public Domain in most countries other than the UK.

Aspects of Anglo-Saxon medicine even stand up to modern laboratory testing. In one remarkable example, researchers recently discovered that a remedy for eye infections found in Bald’s Leechbook, dating from the 10th century, was effective in tests against a strain of the antibiotic-resistant bacterium MRSA.

Bald’s Leechbook

A text page from Bald's Leechbook, featuring recipes written in Old English.

A large collection of medical remedies in Old English (British Library, Royal MS 12 D XVIII, f. 12v)

View images from this item  (4)

Usage terms

Public Domain in most countries other than the UK.

The Anglo-Saxons also experimented with a variety of scientific instruments, from portable sundials and candle clocks to flying machines. According to William of Malmesbury (died c. 1143), a monk called Æthelmaer, who lived at that abbey in the 11th century, invented a device that enabled him to glide from a tall tower, although he landed badly and was not allowed to try it again!

Other Anglo-Saxons experimented with civil engineering: Bishop Æthelwold of Winchester (963–984) reportedly diverted a stream to provide running water for one of his churches.

Anglo-Saxon astronomy, mathematics and timekeeping

Astronomy had practical value in this period. Knowledge of the stars was important for timekeeping, from calculating the days of the calendar year to measuring hours using sundials.

It was especially important for Christian communities to be able to calculate the solar and lunar years, since the date of their most important holy day, Easter, changed from year to year, based on when a full moon fell after the Spring equinox.

The formula for calculating Easter is rather complicated and was the subject of a major meeting in 664, known as the Synod of Whitby.

The form of mathematics devoted to calculating the date of Easter was known as computus. Bede was an important figure in this field, and he discussed the subject in his work De temporum ratione (‘On the reckoning of time’).

The Reckoning of Time

A page from a miscellany of works on computus and astronomy, featuring a diagram that details the technique of finger-counting.

The Reckoning of Time deals with computus, the science of time-reckoning and how to calculate the date of Christian holy days such as Easter (British Library, Royal MS 13 A XI, f. 33v)

View images from this item  (4)

Usage terms

Public Domain in most countries other than the UK.

As well as studying the stars to calculate the calendar, some Anglo-Saxons studied the movement of the planets. The libraries of Anglo-Saxon monasteries often contained earlier texts on the planets and the stars, while Anglo-Saxon scholars learned from their contemporaries from other regions. 

For example, Abbo of Fleury spent two years in England in the 980s, and he developed a diagram showing how the planets moved through the night sky over time.

Anglo-Saxon medicine

Anglo-Saxon medical manuscripts typically contained remedies based on plants and animals. Many of these were inherited from the works of earlier writers living around the Mediterranean, as is the case in the remedies in this Old English illustrated Herbal. Remedies for poisonous bites were marked out with drawings of snakes and scorpions.

Old English Illustrated Herbal

A page from the Old English Herbal, featuring an illustration of a plant entwined with three serpents.

Recipes for medical remedies made using parsley and cabbage (British Library, Cotton MS Vitellius C III, f. 57r)

View images from this item  (6)

Usage terms

Public Domain in most countries other than the UK.

The manuscript also includes texts on the medicinal properties of badgers and another on medicines derived from parts of four-legged animals.

The Anglo-Saxons continued to have links with, and to seek medical advice from, experts living in distant lands. For example, Patriarch Elias of Jerusalem (reigned c. 879–907) reportedly sent medical advice and medical aids to King Alfred of Wessex (reigned c. 871–899), who suffered from a chronic, debilitating disease.

In addition to herbal and animal-based salves and medicines, other medical techniques such as blood-letting were employed in Anglo-Saxon England. Our modern word ‘leech’, a creature which is synonymous with medicine of the era, is derived from the Old English word for physician, laece.

Bald’s Leechbook contains a number of remedies for everyday ailments:
  • For a headache (head wark), crush together some beetroot and honey, smear the juice over the patient’s head, and then have them lie on their back in the sun and let the juice run down their face.
  • For swollen eyes, cut off a live crab’s eyes and put them against the patient’s neck.
  • For shingles, use a salve made from the bark of 15 types of tree including ash, oak and apple.
  • For excessive bleeding, apply horse dung to the wound.

Even plastic surgery, which we may think of as a modern practice, is mentioned. To cure a cleft palate, ‘pound mastic [resin from a mastic tree] very small, add an egg white… cut with a knife the edges of the lip, sew with silk, then smear the salve inside and outside or the silk will rot’.

In many cases, remedies also included some element of performance, involving ritual or repeated actions and the chanting of particular formulas or forms of words, often in languages other than English. Early medieval people often turned to prayers for healing, as can be seen in prayerbooks and collections of saints’ miracles.

Narratio Metrica de Sancti Swithuno

A text page from a collection of liturgical material relating to St Swithun.

Description of miracles associated with St Swithun in the late 10th century (British Library, Royal MS 15 C VII, f. 124v)

View images from this item  (4)

Usage terms The British Library has decided to make the images of pre-1800 collection items available on this website. For more information please refer to the following guidance.

  • Alison Hudson
  • Alison Hudson is Project Curator of Anglo-Saxon Manuscripts at the British Library, working on the Anglo-Saxon Kingdoms exhibition. Her doctoral research at the University of Oxford focused on the English Benedictine reform movement in the 10th century.