MAGNA CARTA AND COMMERCE. This article by Nicholas Vincent explains how some of the clauses of magna Carta promoted trade and markets. Clause 33 provides: “All kydells for the future shall be removed altogether from Thames and Medway, and throughout all England, except upon the seashore.” If you trace “kydell” on wiktionary, you get to “kiddle”, which is: “A kind of fishweir resembling a wattle or fence”. Vincent explains that these were fish-weirs which trapped fish but slowed the flow of water and led to silting. Magna Carta came down on the side of the free movement of goods on the water.
Clause 35 provides: “Let there be one measure of wine throughout our whole realm; and one measure of ale; and one measure of corn, to wit, ‘the London quarter’; and one width of cloth (whether dyed, or russet, or ‘halberget’), to wit, two ells within the selvedges; of weights also let it be as of measures.” Standardization of weights and measures promoted trade throughout the country.