The chapters that follow look at the ways in which the major trade routes of the late medieval western Mediterranean were transformed by a series of related developments in the Catalan political world: the conquest and settlement of the Balearic islands from 1229 onwards; the creation by the will of James I of Aragon of the notionally independent kingdom of Majorca; and then the reincorporation of this kingdom into the lands ruled by the king of Aragon and count of Barcelona after 1343. The subject is thus not simply the commerce of the island of Mallorca and the kingdom of Majorca, but the relationship between the changing views of the function of the Majorcan kingdom in the Aragonese commonwealth and the expansion or contraction of its trade that accompanied its changing status. An attempt is made to place the kingdom's trade in a wider context by looking at Latin trade with the Balearics before the Catalan invasion of 1229, and at the trade of Mallorca after the fall of the autonomous kingdom in 1343. Above all, this study seeks to examine the trade of Mallorca mainly by way of the documents left by the merchants themselves, such as the commercial contracts for trade to and from Mallorca.