Romeo and Juliet takes place in the northern Italian cities of Verona and Mantua. There is some disagreement about the time the play is set. Some experts believe that we cannot firmly pin down exactly when the play takes place, though conventionally, it is set in Renaissance Italy (which includes the 14th and 15th centuries). However, there is nothing in the play that explicitly dates it to this time. The Nurse in the play mentions that an earthquake occurred eleven years before when she says, "'Tis since the earthquake now eleven years" (Act I, scene 3, line 25). Some experts believe this is a reference to the Dover earthquake of 1580, which would place the action of the play in 1591. However, the exact date when the action of the play unfolds is still a matter of debate among Shakespearean scholars.
Thomas, Sidney. "The Earthquake in Romeo and Juliet." Modern Language Notes Vol. 64, No. 6 (Jun., 1949), pp. 417-419. Published by: The Johns Hopkins University Press. DOI: 10.2307/2908604. Stable URL: http://www.jstor.org/stable/2908604