The Commercial Revolution was a period of European economic expansion, colonialism, and mercantilism which lasted from approximately the late 13th century until the early 18th century. It was succeeded in the mid-18th century by the Industrial Revolution. Beginning with the Crusades, Europeans rediscovered spices, silks, and other commodities rare in Europe. This development created a new desire for trade, and trade expanded in the second half of the Middle Ages. European states, through voyages of discovery, were looking for new trade routes in the 15th and 16th centuries, which allowed the European powers to build vast, new international trade networks. Nations also sought new sources of wealth. To deal with this new-found wealth, new economic theories and practices were created. Because of competing national interest, Europeans had the desire for increased world power through their colonial empires. The Commercial Revolution is marked by an increase in general commerce, and in the growth of financial services such as banking, insurance, and investing.