Showing posts with label mappa mundi. Show all posts
Showing posts with label mappa mundi. Show all posts

Tuesday, November 13, 2012

The Flat Earth

In 1620, Sir Francis Bacon published Novum Organum ("The New Organon," by which he meant a new interpretation of nature). In it, he claimed that the ancient fathers of the Christian church did not tolerate a belief in a round Earth. It is probably this work that influenced the popular belief ever since that the Middle Ages, or religion, were steadfast in their belief in a flat Earth.

There is plenty of evidence to the contrary, however. True, there was "evidence" in the Middle Ages of a flat Earth. The Mappa Mundi (Map of the World), meant to portray the part of the world believed to be habitable, does make the world look flat and finite. Way back in he 3rd century BCE, however, Eratosthenes had coined the term "geography" and measured the circumference of the clearly round Earth by noting the difference in shadows of a stick at noon on two points many miles apart; the angles and length of the shadows told him that the sun was shining down on the surface at different angles, and the surface was therefore curved.

As revered an early christian as Boethius (480-524, mentioned here) in De consolatione philosophiæ (The Consolation of Philosophy) reminds us of how small we are in the grand scheme of things with this:
It is well known and you have seen it demonstrated by astronomers, that beside the extent of the heavens, the circumference of the earth has the size of a point; that is to say, compared to the magnitude of the celestial sphere, it may be thought of as having no extent at all.
Medieval sources even quote Pliny the Elder's figure of 29,000 miles for the circumference, a remarkably accurate figure.*

So was there a conflict between science and Christianity? Depends who you talk to, I suppose. William of Conches (1085-1154), who may have been a tutor to the young man who became King Henry II of England, wrote extensively on reconciling the origin of the cosmos in Plato's Timaeus with Genesis. The Bible may have described the earth as flat, but William knew this should not be taken literally, explaining:
The authors of Truth are silent on matters of natural philosophy, not because these matters are against the faith, but because they have little to do with the upholding of such faith, which is what those authors were concerned with.
As learning spread—specially with the advent of mass printing—perceptions of the Earth's shape would have spread thanks to re-printed classical works. Columbus' idea to go west to arrive at an eastward point was not a risky gamble or a brilliant insight. Other "facts" in the Bible were also understood to be not literal: Pope Innocent III, for instance, knew that the Moon shone with reflected light, even though the Bible refers to the Sun and Moon as "two lights."

So what account for the learned Bacon's statement? It may have something to do with the conflict between Galileo and the Church. Although the famous trial would not take place until 1633, Galileo had received a formal Admonition in 1616, warning him:
to relinquish altogether the said opinion that the Sun is the center of the world and immovable and that the Earth moves; nor further to hold, teach, or defend it in any way whatsoever, verbally or in writing; otherwise proceedings would be taken against him by the Holy Office; which injunction the said Galileo acquiesced in and promised to obey.  [link]
It is very likely that Bacon and the rest of Europe's scientific community was aware of this growing conflict. In this historical context, Bacon's statement can be seen as a condemnation of the Church because of a recent action—even though for centuries the knowledge of a round Earth was common.

*In fact, the original figure might have been more accurate than we suspect: it was given in Greek stadia, a measurement which meant different things to different users. Our best interpretation is 29,000 miles, but if Pliny were using stadia of a slightly shorter length... .

Sunday, June 24, 2012

Gervase of Canterbury

Gervase of Canterbury (c.1141-c.1210) was a monk of Christ Church in Canterbury. He was ordained on February 16, 1163 by Archbishop of Canterbury Thomas Becket (who would be assassinated in 1170, canonized by Alexander III a few years later, and become the focus of the most famous shrine in England).

Gervase had a fairly undistinguished career as a monk, and his "importance" for us is in his connection to other people and events. He was involved in the dispute between the monks of Christ Church and Archbishop of Canterbury Baldwin of Forde. Baldwin disapproved of the luxury in which the monks of Christ Church lived, derived from the donations made by pilgrims to the shrine of St. Thomas Becket. At one point, Baldwin had the entire monastery confined under house arrest for a year and a half. Gervase was one of the monks sent to inform Baldwin that they were making an appeal to the pope. Ultimately, the monks were given their freedom and normalcy restored (except that Baldwin appointed Roger Norris, a pretty ineffective administrator, as their prior).

For a brief time Gervase held the position of sacristan (the person who takes care of the church and its contents), working for the Archbishop Hubert Walter.

...and that's about it for Gervase, except for one little thing that has intrigued historians and astronomers for centuries. Gervase kept records and wrote books, such as a history of the Archbishops of Canterbury and his Mappa Mundi, which lists bishoprics and ecclesiastical houses in England, Wales and Scotland. He was also the chronicler of his monastery, and on the night of June 18th, 1178,* he recorded something curious and previously unseen.

...but what the event was, and how June the 25th is actually the anniversary of the event on the 18th, I'll save for tomorrow.

*The same year this was happening in Italy, as mentioned on the June 20th post.

Saturday, June 23, 2012

Mappa Mundi

Approximately 1100 mappae mundi (maps of the world) have survived from the Middle Ages; about 200 are separate maps; the rest are in books.

Maps of the world were obviously limited by knowledge of geography. This did not deter medieval cartographers, however, since maps existed for along time not as guides for travelers, but as diagrams of the layout of God's creation. Minutiae weren't as important as portraying the overall plan, or showing a particular feature. For instance, Gervase of Canterbury's Mappa Mundi was drawn up specifically to show the bishopric s and ecllesiastical foundations of England, Scotland and Wales.

One of the most common of the map designs was the T-O design, called that by modern scholars because it resembled those letters. The "T" was the division of the major landmasses with the enormous Asia topping Europe and Africa; "O" was the encircling Ocean.

Note that Asia is on top. When choosing proper positioning for the arrangements of the continents, the direction of the rising sun seemed to be a logical place to begin. East is therefore placed at the top of the maps, and the arrangement of things in their proper place on a map therefore was called "orienting."*

Cicero's Dream of Scipio (in which a vision of the world is viewed in detail) was very popular in the Middle Ages for what it had to say about the world and the divine. Macrobius' (5th century CE) Commentary on it was how many readers became familiar with it. Many copies of the Commentary include mappa mundi of the type therefore called Macrobian. The Dream includes a description of the various zones, cold to temperate to hot to temperate to cold. Only the temperate zones were considered habitable.

Fourteen manuscripts of Beatus of Liébana's (c.730-800) popular Commentary on the Apocalypse of St. John include the quadripartite-style map that squeezes the Antipodes into the extreme south.

The most famous and most detailed maps provide the most variety and data and start to approach the realism and usefulness of modern cartography. The symbolic value of the mappae mundi began to be replaced by the need for accurate information to aid in travel and, especially, navigation on the seas. The new "Portolan Charts" became far more valuable to have and reproduce, and the number of mappa mundi were produced less.

If you would like to see some maps from across the ages, a good start is the Imaginary Museum.

*An extra tidbit: "orient" comes to Middle English from Latin via French and the verb oriri, "to rise"; once in English it starts being used for the direction itself in which the sun rises.