ruler isn't just wrong; it's positively diabolical. Macbeth actively conspires with the forces of darkness in murdering King Duncan, and it's clear that Shakespeare regards any would-be usurper or assassin as having entered into a similarly Satanic pact.

William Shakespeare (1564-1616) lived and wrote most of his plays during the reign of Queen Elizabeth I (1558-1603)—the Elizabethan era--and ended his career during the early years of the reign of James I (1603-1625)—the Jacobean era ( not to be confused with the reign of King James VI of Scotland).  Shakespeare wrote his most famous tragedies at the time when the monarchies were changing, roughly 1600-1610 (Hamlet, Troilus and Cressida, Othello, King Lear).  He then retired to Stratford-upon-Avon, where he died.  The Elizabethan era was an exciting time for all the arts (to a great degree because Elizabeth was a theatre-lover), and a relatively stable time politically, making theatre expansion safe and fruitful for Shakespeare and his contemporaries.  The Jacobean theatre changed somewhat, becoming bloodier and coarser as London audiences became more and more demanding of stage violence.

The first and longest ruling monarch was Elizabeth I who ruled for what might be thought of as the first half of Shakespeare's writing career. Many of the issues to do with marriage and the issues to do with whether one should marry according to the will of others was particularly pertinent to the plays written during her reign. Plays which contain these themes that are particularly striking include The Merchant of Venice, critically believed to have been written and performed in 1596-7, and A Midsummer Night's Dream, most likely performed in 1595. Elizabeth's rule is particularly pertinent in this respect as she never married despite considerable pressure to do so, not least early in her reign when this pressure came from the widower of her deceased sister, King Phillip II of Spain. Having been rejected, Phillip attempted to lead a large invading force on England via the Spanish Armada, a large invasion fleet. The armada was, however, defeated despite their far greater numbers, cementing Elizabeth's popularity amongst many and making English victory another popular theme in Shakespeare's plays, perhaps most markedly in 1599's Henry V which dramatises the victory of Henry V, another English monarch, against great odds at the Battle of Agincourt. 

The other monarch under whom Shakespeare wrote his plays was James I of England. Before taking the English crown in 1603, James had been James VI of Scotland and was the first to unite the two thrones. Macbeth (1606), also known as 'the Scottish Play' is cited by Peter Ackroyd, a famous modern biographer of Shakespeare, as having its setting during a period of enthusiasm for Scotland that came after James's accession to the English throne. Given that Elizabeth I died unmarried and without a direct heir, some of the anxiety of the population about who would take the thrown upon her death might be imagined as a sub-text to another of Shakespeare's tragedies, King Lear (1605-6) which tells of the bloody civil war which struck ancient Britain after an ageing monarch stepped down from the throne. 

During the life of William Shakespeare there were two monarchs that ruled England. The first was Henry the eights and the second was Elizabeth the first. Both were impressed with Shakespeare and commissioned him to write plays. This is one of the conditions of his success. There is alos some evidence that he was a member of a traveling theater group and did some teaching. In 1594, he became an actor and playwright for Lord Chamberlain’s Men. In 1599, he became a part owner of the prosperous Globe Theater.