Mary I of England, often referred to as "Bloody Mary," was the first queen regnant of England, reigning from 1553 to 1558. Born in 1516, she was the daughter of King Henry VIII and his first wife, Catherine of Aragon. Her early life was marred by the tumultuous relationship between her parents, which eventually led to the English Reformation. When Henry sought to annul his marriage to Catherine in pursuit of Anne Boleyn, the Catholic Church refused, leading him to sever ties with the church and establish the Church of England. Consequently, Mary, a devout Catholic, was declared illegitimate and removed from the line of succession, only to be reinstated later.

During her youth, Mary faced challenges due to her parents' contentious divorce and her father's subsequent marriages. Her staunch Catholic faith, instilled by her mother, put her at odds with the Protestant reforms under her father's reign and later, under the brief reign of her half-brother Edward VI. When Edward died in 1553, he attempted to exclude both Mary and her sister Elizabeth from succession in favor of Lady Jane Grey. However, Mary garnered significant support and was proclaimed queen, deposing Jane.

Mary's reign is best remembered for her efforts to re-establish Catholicism in England. This religious fervor was marked by the persecution of Protestants; under her rule, hundreds of Protestants were burned at the stake, earning her the epithet "Bloody Mary." Her religious policies, however, were largely undone by her successor and half-sister, Elizabeth I.

One of Mary's significant political actions was her marriage to Philip II of Spain in 1554. The union was unpopular with the English populace, as it stoked fears of Spanish influence and potential control over the English throne. This marriage also led to England's involvement in Philip's war against France, culminating in the loss of Calais, England's last possession in France.

Her relationship with Parliament was tense, primarily due to religious matters. While the Parliament approved her religious reversions, her marriage treaty with Philip was met with stiff opposition.

Regarding foreign relations, her alignment with Spain through marriage brought her into continental conflicts. Her reign, though short, saw a stark shift from the Protestant leanings of Edward VI back to Catholic orthodoxy, only for the pendulum to swing back to Protestantism under Elizabeth I.

Mary had no children, a source of great sorrow to her and a political concern for the continuity of the Tudor line. Her inability to produce an heir and her staunch Catholic policies increasingly alienated her from her subjects.

She died in 1558, likely of ovarian or uterine cancer. At the time of her death, while many Catholics mourned her, the Protestant majority, bearing grievances from her persecutions, felt relief. Her death heralded the beginning of Elizabeth I's reign, often termed the "Golden Age" of English history.

The era was characterized by great religious tension, a continuation from Henry VIII's break from Rome. While the Renaissance was in full bloom on the continent, its influence began seeping into England, laying early seeds for the Elizabethan era's cultural blossoming. Society was in flux, with religion driving a wedge between families, communities, and the political elite.