Final answer:
The end of feudalism and the rise of cities and commerce were the most significant transformations Europe experienced before 1492, setting the stage for explorations leading to colonialism and global trade.
Step-by-step explanation:
The most significant transformation that Europe experienced in the three centuries before 1492 was the end of feudalism and the rise of cities and commerce. This period, often known as the Late Middle Ages, saw a demographic explosion in which the population of Europe doubled. This population growth led to the emergence of large cities such as Venice, Florence, and Milan, each boasting over 100,000 inhabitants by the 13th century. The decline of the feudal system, wherein people were previously tied to the land under lords, facilitated the migration of people to urban areas and contributed to the development of commerce and trade. By the 15th century, European exploration expanded due to commercial interests, leading to the eventual colonialism and the formation of new trade routes.
These transformations were driven by various factors such as the agrarian revolution, an increased demand for luxury goods, and the desire to improve trade and communications with the rest of the world, particularly following the Black Death and other crises that weakened feudal powers. Venice and Genoa, in particular, took the lead in trading with the East, attempting to bypass the Muslim middlemen that controlled the Silk Road. This era set the stage for Columbus's voyage in 1492 and the beginning of the era of European colonialism and worldwide trade, which would irreversibly change the global balance of power.