Julius Caesar

What is the relevence of the play Julius Caesar to the time?

I'm not sure if you're asking about the relevance of the play to Shakespeare's time (the time the play was written) or the time the play was set (Julius Caesar's lifetime in Rome).  However, the play is about moral ambiguity in a political setting and the personal tragedy that comes from that.  This is relevant to any time since (unfortunately) there is always moral ambiguity in politics which often results in personal tragedy.

Shakespeare may have been reflecting his own political philosophy about English civil war (there is much evidence that he was concerned about this as it is the subject of many of his history plays) since civil disorder and violence are tragic for the entire society.  We see this time and time again in English history with the war of the Roses, the murder of the Princes in the Tower (supposedly by Richard III), and the treatment of Henry VIII and his wives.