**Charles de Bouvelles** is also known as Carolus Bovillus. Charles' father was an aristocrat and Charles was born into the wealthy Bovelles family. However Soyecourt, the town of his birth, was in the Ponthieu region of Picardy and during Charles' childhood the region was being fought over. The dukes of Burgundy had acquired Ponthieu in 1435 under the Treaty of Arras which had been signed by Philip the Good of Burgundy and Charles VII of France. After much fighting the region was retaken by France under Louis XI in 1477. Picardy was for many years on the frontier and as a consequence subjected to frequent invasions.

De Bouvelles was educated in Paris. There he was a student of Jacques Lefèvre d'Etaples (1455-1536) who was a famous humanist, theologian, and translator. Ordained a priest, Lefèvre taught philosophy in Paris from about 1490 and it was about the time that de Bouvelles came to Paris. Lefèvre was, of course, from d'Etaples so like de Bouvelles he came from Picardy. While de Bouvelles was studying under him, Lefèvre began to produce student manuals on physics and mathematics and he began working on new annotated translations of Aristotle's works on ethics, metaphysics, and politics. Lefèvre had considerable influence on his student de Bouvelles, who went on to improve on the methods of his teacher.

In 1495 the plague hit Paris and de Bouvelles left without, it appears, taking a degree. In the following years he worked on mathematical topics, in particular trying to solve the classical Greek problem of squaring the circle. In 1501, while trying to solve this problem, he introduced the hypotrochoid (although he did not use this name) which is the curve traced by a point *P* on a circle of radius *b* which rolls round inside a fixed circle of radius *a*. Using this curve, de Bouvelles was able to give a mechanical means of squaring the circle.

In 1503 he published *Geometricae introductionis* in Latin. The book discussed the problem of squaring the circle and gave an account of his various attempts to solve the problem. It was after he completed work on his book that de Bouvelles set out travelling first to Switzerland, and Mainz in Germany. Later he travelled through Italy, Spain, and France. On his return he became a Catholic priest and then became a canon in the Gothic collegiate church at St Quentin back in his home region of Picardy.

After being a canon at St Quentin, de Bouvelles became a canon at the Cathedral of Notre-Dame in Noyon, north-northeast of Paris and still in the Picardy region. The Cathedral there was a fine transitional late 12^{th} century Romanesque-Gothic building in an important ecclesiastical centre. The Bishop of Noyon was Charles de Hangest and he was very pleased with his canon de Bouvelles, granting him much free time to undertake his studies of mathematics, philosophy and theology. In particular Bishop de Hangest had a country estate which provided the peace and quiet that de Bouvelles needed to concentrate on his studies.

In 1509 he published a philosophy book *De Sapiente* in which de Bouvelles presented a dualism between the observer and the observed. He saw human beings as:-

... no longer part of the universe but as its eye and mirror; and indeed as a mirror that does not receive the images of things from outside but that rather forms and shapes them in itself.

So the human observer sees the world as something to dominate and exploit. This work would have considerable influence on Descartes who took de Bouvelles' ideas still further.

In 1510 de Bouvelles published another work on mathematics. This was *Liber de XII numeris* which studied perfect numbers. It is not a particularly deep work and some of the properties that de Bouvelles gives are left unjustified. Another work *Geometrie en francoy* has the distinction of being the first geometrical treatise printed in French. We noted that *Geometricae introductionis* was first published in Latin but the work proved quite popular and so translations were in order. A French translation was published in 1542 and, five years later, the work appeared in Dutch.

De Bouvelles remained in Noyon for the rest of his life, teaching philosophy but seldom celebrating mass.

**Article by:** *J J O'Connor* and *E F Robertson*