Who were the two monarchs that ruled with power during Shakespeare's life?

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.