Elizabeth I was born in 1533 to Henry VIII and Anne Boleyn. Although she entertained many marriage proposals and flirted incessantly, she never married or had children. Elizabeth, the last of the Tudors, died at seventy years of age after a very successful forty-four year reign.
Elizabeth came to the throne in 1558 widely read and highly educated. She could translate Greek, Latin, French, Italian, Spanish, and German. During the age that was named for her, she became the muse of many artists and the subject of many poems and plays.
She was, as Herbert notes, the wellspring from which all creative works flowed and was, in essence, a co-creator of them. Writers considered her to embody the female power associated with such mythological and biblical figures as Judith, Esther, and Minerva, and some--like Edmund Spenser--worked to associate her with a romance tradition, the Arthurian legend, that legitimated her crown and gave to England a glorious past.
Queen Elizabeth contributed her own works to an English literary tradition through translations, speeches, and poetry.
Her poem "The Doubt of Future Foes" focuses on the danger presented to the crown, and hence to England as a whole, by the innumerable foes who confronted or would confront Elizabeth. It was inspired by the Queen's Roman Catholic cousin, Mary Stuart, Queen of Scots (mother to James I of England, the first Stuart monarch), who sought refuge in England in 1568 to escape her rebellious subjects. Opponents to Elizabeth had often plotted to place Mary on the throne, but their attempts failed. The poem is notable for its sustained botanical imagery: when the Queen writes of "polling the tops" of her opponents, she clearly threatens them with beheading.
"On Monsieur's Departure" might have been written to the French duke of Anjou, a former suitor (although this is unlikely!), or to the Earl of Essex, one of her favorite courtiers (more likely!).