Romeo and Juliet is set in the real city of Verona, Italy, likely during the 14th or 15th centuries (a century or two before Shakespeare wrote the play). Verona is depicted as a battleground of sorts, ruled by a prince who attempts to restore order between two feuding, fictional families, the Capulets and Montagues, and their allies. In reality, Verona's early modern history is littered with similar feuds between wealthy families who attempted to gain control over the city and its citizens—reflecting Shakespeare's keen interest in using history as a point of departure for his plays, which embellished facts with fiction.
Italy was also a common setting for both Shakespearean tragedies and comedies, including The Taming of the Shrew, Much Ado About Nothing, Othello, and Julius Caesar, as well as The Two Gentlemen of Verona, which is also set in Verona. Shakespeare and English theater-goers of his era viewed Italian culture as distinctly foreign, and would have associated a rich range of experiences and emotions with Italy, such as passion, lust, jealousy, and violence—all themes that crop up in Romeo and Juliet.
In contrast, Shakespeare's histories, set in England, Scotland, and Wales, often seem more staid and formal, analyzing power struggles between historic rulers and their successors. This is in part because widespread censorship in England during Shakespeare's time endangered writers and critics who approached controversial topics like sex, tyranny, and uncontrolled passions, particularly in the context of English culture. England was held up as a civilized, orderly society; any suggestion that this might not always be the case could provoke suspicion from the monarchy and government. Italy, though, was a prime setting for Shakespeare to explore these subjects, associating them with foreigners while subtly noting their universality.