By 1200 there were reasonably accurate Latin translations of the main works of Aristotle, Euclid, Ptolemy, Archimedes, and Galen, that is, of all the intellectually crucial ancient authors except Plato. Also, many of the medieval Arabic and Jewish key texts, such as the main works of Avicenna, Averroes and Maimonides now became available in Latin. During the 13th Century, scholastics expanded the natural philosophy of these texts by commentaries and independent treatises. Notable among these were the works of Robert Grosseteste, Roger Bacon, John of Sacrobosco, Albertus Magnus, and Duns Scotus. Precursors of the modern scientific method can be seen already in Grosseteste's emphasis on mathematics as a way to understand nature and in the empirical approach admired by Roger Bacon. Grosseteste was the founder of the famous Oxford Franciscan school, and based his work on Aristotle's vision of the dual path of scientific reasoning. Concluding from particular observations into a universal law, and then back again: from universal laws to prediction of particulars. Grosseteste called this "resolution and composition." Further, Grosseteste said that both paths should be verified through experimentation in order to verify the principals. These ideas established a tradition that carried forward to Padua and Galileo Galilei in the 17th Century.

Roger Bacon described a repeating cycle of observation, hypothesis, experimentation, and the need for independent verification. He recorded the manner in which he conducted his experiments in precise detail so that others could reproduce and independently test his results - a cornerstone of the scientific method, and a continuation of the work of researchers like Al Battani. He contributed to the development of optics, and is also thought to have developed compasses, telescopes, gunpowder and firearms based on examples that Marco Polo and other merchants brought back from China.

3. Economic Environment

Background

In the High Middle Ages, urban life revived along with trade, commerce and the money economy, while agriculture developed the two-field method that left one field fallow in each season (Medieval Economics). Norman institutions like serfdom "were superimposed on an existing system of open fields and mature, well-established towns involved in international trade" (Dyer 14). Despite economic dislocation in urban and extraction economies "including shifts in the holders of wealth and the location of these economies, the economic output of towns and mines developed and intensified over the period" (Hatcher 40). In England, the population grew from 1.5 million in 1086 to 4-5 million in 1300, although the majority of these were peasants and serfs (Hodgett 148; Kowalski 248). More land was "brought into production to feed the growing population or to produce wool for export to Europe" (Bailey 41). Mining increased in England, with the silver boom of the 12th century helping to "fuel a fast-expanding currency" (Dyer 115).

Towns

By the late-11th Century more than a hundred towns had developed with a combined population approaching 200,000, and by 1300 about 600 towns existed, including forty with populations over 2,000. Burghers and bourgeoisie (town dwellers) received charters of self-rule from medieval kings and aristocrats, and by 300 had won "the rights to regulate trade, levy taxes and hold courts" (Medieval Economics). Trade, commerce and the circulation of money kept expanding, at least until the crisis of famine and plague inhibited these developments in the 14th Century. A new class of merchants evolved in the towns that believed in liberalism and free enterprise, and became a third force between the aristocracy and peasantry (Medieval Economics).

Agriculture

Wheat remained the single most important crop, followed by but rye, barley and oats were (Bailey 44). Sheep, cattle, oxen and pigs were common, "although most of these breeds were much smaller than modern equivalents and most would have been slaughtered in winter" (Dyer 25). New villages had adopted an open field system "in which fields were divided into small strips of land, individually owned, with crops rotated between the field each year and the local woodlands and other common lands carefully managed" (Dyer 19-29). Most peasants were tied to the land and had to pay rents to the aristocracy in cash or kind (Bartlett 313). This early English economy was not entirely at subsistence level "and many crops were grown by peasant farmers for sale to the early English towns" (Dyer 14-26). At the same time, the number of slaves decreased and the Anglo-Saxon nobility gradually merged with the Normans...

Fishing became an important trade along the English coast, especially in Great Yarmouth and Scarborough (Bailey 51-53). Most of the peasant population lived in great poverty, though, and "records of household belongings show most possessing only 'old, worn-out and mended utensils' and tools" (Dyer 174).
Taxation

William enforced the collection of taxes be his shire reeves (sheriffs) and imposed new taxes on trade. He also commissioned the Domesday Book in 1086, "a vast document which attempted to record the economic condition of his new kingdom" (Douglas 299-302). Norman kings adopted the French feudal aid model, "a levy of money imposed on feudal subordinates when necessary; another method was to exploit the scutage system, in which feudal military service could be transmuted to a cash payment to the king" (Lawler and Lawler 6). These were increasingly unpopular and, along with the feudal charges, were condemned and constrained in the Magna Carta of 1215. As part of the formalisation of the royal finances, "Henry I created the Chancellor of the Exchequer, a post which would lead to the maintenance of the Pipe rolls, a set of royal financial records of lasting significance to historians in tracking both royal finances and medieval prices" (Bartlett 159).

In 1275, the Great and Ancient Custom began to tax woolen products and hides," with the Great Charter of 1303 imposing additional levies on foreign merchants in England, with the poundage tax introduced in 1347" (Hodgett 203). In 1340, the discredited tallage tax system was finally abolished by Edward III. Assessing the total impact of changes to royal revenues between 1086 and 1290 is difficult. At best, Edward I was "struggling in 1300 to match in real terms the revenues that Henry II had enjoyed in 1100, and considering the growth in the size of the English economy, the king's share of the national income had dropped considerably" (Carpenter 51).

Trade

Unable to produce much they were often left to purchase items at a cost that exceeded their income. Compensation for these small holders came again "in the economic advances of the wealthier peasants. Private employment, steady wages and annual taxation took its roots in this byproduct of the expansion of the medieval market" (Medieval Economics). Some towns, such as York, "suffered from Norman sacking during William's northern campaigns. Other towns saw the widespread demolition of houses to make room for new motte and bailey fortifications, as was the case in Lincoln" (Douglas 313). In the years immediately after the invasion, a lot of wealth was drawn out of England in various ways by the Norman rulers and reinvested in Normandy, "making William immensely wealthy as an individual ruler" (Douglas 303-304).

New towns were usually located with access to trade routes in mind rather than defense, and the streets were laid out to make access to the town's market convenient. A growing percentage of England's population lived in urban areas, and "estimates suggest that this rose from around 5.5% in 1086 to up to 10% in 1377" (Pounds 80). London was also "an important hub for industrial activity; it had many blacksmiths making a wide range of goods, including decorative ironwork and early clocks (Geddes 174-175). The increasing wealth of the nobility and the church "was reflected in the widespread building of cathedrals and other prestigious buildings in the larger towns, in turn making use of lead from English mines for roofing" (Bailey, 46). Land transport remained much more expensive than river or sea transport during the period (Bartlett 361). Shipbuilding generally "remained on a modest scale and economically unimportant to England at this time," while transport remained very costly in comparison to the overall price of products (Hodgett 109). A large number of bridges were built during the 12th century to improve the trade network (Bartlett 364).

Money Supply

William the Conqueror maintained the old system of standardized coinage and used the term "sterling" as the name for the Norman silver coins (Stenton 162). Subsequent kings continued to increase control over coinage throughout the 13th century (Stenton 169). Before the Norman invasion "there had been around £50,000 in circulation as coin, but by 1311 this had risen to more than £1 million" (Bailey 49). As a result, coins were being "moved in barrels and sacks to be stored in local treasuries for royal use as the king travelled" (Stenton 163).

Mining

Four metals were mined commercially in England during the period, "namely iron, tin, lead and silver; coal was also…