Shakespeare does not specify an exact year for the setting of his romantic tragedy; however, Romeo and Juliet is designated as occurring during the fourteenth century.
This time frame is appropriate for the story of the fated, turbulent, and violent love of Juliet and Romeo since the fourteenth century was a break between the Medieval Age and the Renaissance, and it was marked by great turbulence with two natural disasters: the "Little Ice Age" and the Black Plague. Also, the Hundred Years War was in progress until 1450. There was also great turbulence within Christendom as the Papal seat was moved from Rome to Avignon, France, and the pope who was appointed was hated by Rome.
The so-called Great Western Schism lasted until 1447, during which time there were rival Popes in Rome and Avignon. Since the Catholic Church based its claim to authority on an unbroken succession of Popes, the existence of two parallel papacies was more than just a power struggle; it was a fundamental challenge to the whole medieval world-view.
Thus, the microcosm of Romeo and Juliet's world with its rivalries and feuds, it disease in Mantua, and its violence mirrors the macrocosm of the historical world.