1450 represents a good starting point for the examination of a 300-year period because it was only three years later that Constantinople fell to the Ottoman Empire. This came as a shock to Europe, because the city was the single remnant of the Eastern Roman Empire (or Byzantine Empire). Europe now felt itself even more vulnerable to an onslaught from the east. This, in part, was a motivation for the exploration and colonization which began, even before the voyage of Columbus, with the Portuguese navigator Bartolomeu Dias's expedition around Africa in 1488. With the voyage of Columbus and the "discovery" by Europeans that another continent lay to the west (though Columbus himself continued to believe it was Asia he had reached), the floodgates were open. One expedition after another was initiated, and Europe sought to enrich itself through contact with other worlds and the exploitation of labor and resources in those lands. In the same year as Columbus's first voyage, Spain was unified and the last Moorish stronghold, in Granada, was defeated, with non-Christians, both Muslim and Jewish, exiled from Spain or killed if they did not convert to Christianity.
The religious world of Europe was further thrown into turmoil with the Protestant Reformation and the secession of England from the Roman Catholic Church in the first half of the sixteenth century. Though the Peace of Augsburg in 1555 was supposed to establish a permanent settlement between Catholics and Protestants in the Holy Roman Empire at the center of Europe, religious wars continued to plague both mainland Europe and the British Isles for the next two hundred years. In the late 1500s, the overall balance of power in Europe shifted as England became a world power and Spain began to weaken. A process of greater consolidation of power in the British Isles began when England and Scotland, in 1603, came under the same monarchy, the Stuarts (though it was not until a hundred years later that England, Wales, Scotland, and Ireland were made into one kingdom officially in the Union Act). Yet throughout the 1600s, both England and mainland Europe were wracked by war. The Civil War in England, and the Thirty Years' War, in which nearly every major power in mainland Europe was involved, were indications that in spite of their enrichment and growing power through the colonization of the New World, warfare was the normal state of affairs, and the Europeans were at each others' throats as always. And the slave trade came to be a crucial factor in the European and world economies.
With the defeat of Ottoman forces outside Vienna in 1683, the Ottoman Empire was no longer a danger to Europe. By 1750, the end of the period we're examining, Europe as a whole was more powerful than ever. In contrast to three hundred years earlier, Europeans were divided in religion and were no longer in the (relatively) isolated position with respect to other continents and cultures in which they had been in 1450. Also, the invention of printing at the beginning of that three-century period had resulted in a vast dissemination of books and knowledge and a huge increase in the general educational level of Europeans. In just the first half of the 1700s, even further changes in European thought had occurred, partly due to the prestige of science and the discoveries of Newton, which stimulated a new secular orientation among intellectuals. In Britain, the skeptical philosophy of David Hume, and in mainland Europe, the free thinkers Voltaire, Diderot, and others had already begun to transform European thought as a whole.
But what were the factors that showed that in spite of these changes, there was continuity over that period since 1450? Above all, what remained the same was the constant power struggle among the different countries. In 1750, the Seven Years' War (1756–1763) was just around the corner. This was a huge conflict, in some sense the first "world" war, because it was fought on multiple continents—in Europe, America, and Asia. The results of this war set the stage for both the American and French Revolutions.