One reason the Renaissance began in Italy was that Italian city-states

One major reason the Renaissance began in Italy is linked to geography. The city-states of Italy, positioned on the Mediterranean Sea, were centers for trade and commerce, the first port of call for both goods and new ideas.
REFUGE OF SCHOLARS
Secondly, Italy was the core of the former Roman empire, and, at the collapse of the Byzantine empire in 1453, became the refuge for the intellectuals of Constantinople who brought with them many of the great works of the ancient Greeks and Romans, works that had been lost to the West during the Dark Ages. Prior to this, scholars in Italy had been examining the works of the ancients, but they were of poor quality and often incomplete.
VACUUM OF LEADERSHIP
The third reason was political. Due to various political intrigues, the Holy Roman Empire had essentially lost power in northern Italy, the papal states were governed by various leading families within each region, and the city of Naples dominated the South. This vacuum of leadership allowed merchant families to gain considerate power within each city-state and thus revised the laws governing banking, commerce, shipping, and trade. This freer atmosphere led to a busy exchange of both goods and ideas.
INFLUENCE OF THE CHURCH
The Renaissance was a rebirth of ancient Greek and Roman thinking and styles, and both the Roman and Greek civilizations were Mediterranean cultures, as is Italy. The best single reason for Italy as the birthplace of the Renaissance was the concentration of wealth, power, and intellect in the Church. In that time, the Church controlled so much of the political, economic, and intellectual life of Europe, that it gathered most of the best minds, wealthiest men, and most powerful leaders unto itself in Rome at one time or another. The noble merchants of various Italian cities had built up so much wealth over the centuries that they could better afford to patronize the arts and sciences than almost anyone else.