Detailed below, a new regional power arose in the Middle East and spread to Europe starting in the fourteenth century: the Ottoman Turks. In 1453, the ancient Roman city of Constantinople fell to the Turks, by which time the Turks had already seized control of the entire Balkan region (i.e. the region north of Greece including present-day Croatia, Bosnia, Serbia, Albania, and Macedonia). The rise in Turkish power in the east spelled trouble for the east-to-west trade routes the Italian cities had benefited from so much since the era of the crusades, and despite deals worked out between Venice and the Ottomans, the profits to be had from the spice and luxury trade diminished (at least for the Italians) over time.
By the mid-fifteenth century, northern manufacturing began to compete with Italian production as well. Particularly in England and the Netherlands, northern European crafts were produced that rivaled Italian products and undermined the demand for the latter. Thus, the relative degree of prosperity in Italy vs. the rest of Europe declined going into the sixteenth century.
The real killing stroke to the Italian Renaissance was the collapse of the balance of power inaugurated by the Peace of Lodi. The threat to Italian independence arose from the growing power of the kingdom of France and of the Holy Roman Empire, already engaged in intermittent warfare to the north. The French king, Charles VIII, decided to seize control of Milan, citing a dubious claim tied up in the web of dynastic marriage, and a Milanese pretender invited in the French to help him seize control of the despotism in 1494. All of the northern Italian city-states were caught in the crossfire of alliances and counter-alliances that ensued; the Medici were exiled from Florence the same year for offering territory to the French in an attempt to get them to leave Florence alone.
The result was the Italian Wars that ended the Renaissance. The three great powers of the time, France, the Holy Roman Empire, and Spain, jockeyed with one another and with the papacy (which behaved like just another warlike state) to seize Italian territory. Italy became a battleground and, over the next few decades, the independence of the Italian cities was either compromised or completely extinguished. Between 1503 – 1533, one by one, the cities became territories or puppets of one or the other of the great powers, and in the process the Italian countryside was devastated and the financial resources of the cities were drained. In the aftermath of the Italian Wars, only the Papal States of central Italy remained truly politically independent, and the Italian peninsula would not emerge from under the shadow of the greater powers to its north and west until the nineteenth century.
That being noted, the Renaissance did not really end. What "ended" with the Italian Wars was Italian financial and commercial power and the glory days of scholarship and artistic production that had gone with it. By the time the Italian Wars started, all of the patterns and innovations first developed in Italy had already spread north and west. In other words, "The Renaissance" was already a European phenomenon by the late fifteenth century, so even the end of Italian independence did not jeopardize the intellectual, commercial, and artistic gains that had originally blossomed in Italy.
The greatest achievement of the Italian Renaissance, despite the higher profile given to Renaissance art, was probably humanistic education. The study of the Classics, a high level of literary sophistication, and a solid grounding in practical commercial knowledge (most obviously mathematics and accounting) were all combined in humanistic education. Royal governments across Europe sought out men with humanistic educations to serve as bureaucrats and officials, even as merchants everywhere adopted Italian mercantile practices for their obvious benefits (e.g. the superiority of Arabic numerals over Roman ones, the crucial importance of accurate bookkeeping, etc.). Thus, while not as glamorous as beautiful paintings or soaring buildings, the practical effects of humanistic education led to its widespread adoption almost everywhere in Europe.
Even the Church, which continued to educate its priests in the older scholastic tradition, welcomed the addition of humanistic forms of education in some ways. Many of the most outstanding scholars in Europe remained members of the Church, benefiting from both their scholastic and their humanistic educational backgrounds. Erasmus, discussed in the last chapter, was one such priest, as was the most important figure in the Christian Reformation that began in 1517, the German monk Martin Luther.
Likewise, the clear superiority of Italian artists and architects during the heyday of the Renaissance led artists from elsewhere in Europe to flock to Italy. Those artists tended to study under Italian masters, then return to their countries of origin to do their own work. By the middle of the fifteenth century, a "Northern Renaissance" of painters was flourishing in parts of northern Europe, particularly the Low Countries (i.e. the areas that would later become Belgium and the Netherlands). By the sixteenth century, "Renaissance art" was universal in Europe, with artists everywhere benefiting from the use of linear perspective, evocative and realistic portraiture, and the other artistic techniques first developed in Italy.