WAR is the answer i think
Augustus was a Roman emperor who changed the Roman empire from being a democracy into a monarchy again. This is seen as his greatest contribution. Augustus ruled for nearly fifty years. He reinstated some of the ancient traditions, built many monuments, as well as advanced the cultural aspects of the Roman empire. Many influential Latin writers developed their styles during this period. It is believed that the Pantheon was built during his reign. He rebuilt the city of Rome. The Roma
Initially the movement operated chiefly at the local level but it later expanded to the state and national levels progressives drew support from the middle class and the supporters included many lawyers teachers physicians and ministers and business people
Among the 12th and 15th centuries, the European economy was transformed by the interconnecting of river and sea trade routes, producing Europe to become one of the world's most wealthy trading networks. Before the 12th century, the main obstacle to trade east of the Strait of Gibraltar was the absence of commercial incentive rather than inadequate ship design.
Many lands previous unfamiliar to Europeans were discovered by them during this period, though most were already populated. European overseas exploration directed to the advance of global trade and the European colonial empires, with the contact between the Old World (Europe, Asia, and Africa) and the New World (the Americas and Australia).
To sum up, The wealth that could be made through trade was the major motive for the European exploration between 1400 and 1800, letter A.
