House of Tudor
The house of Tudor, which ruled over England from 1485 until 1603, was a family that came to England's throne through good fortune and good timing, more so than through royal descent. Henry VII (r. 1485-1509), the first Tudor monarch, was the son of Margaret Beaufort (1443-1509). Margaret was daughter and only child of John Beaufort, Duke of Somerset (c. 1404-1444), who was the eldest son of John Beaufort, Earl of Somerset (1373-1410). John was a son of John of Gaunt, Duke of Lancaster (1340-1399), third surviving son of King Edward III (r. 1327-1377), through Gaunt's longtime mistress and eventual third wife, Katherine Swynford. The children between John of Gaunt and Katherine became known as the Beauforts, after their birthplace in France (for more information on the house of Beaufort, see here). Although John Beaufort and his three siblings were all conceived out of wedlock and were therefore bastards, they were ultimately legitimized both through papal edict and by King Richard II. As a condition, though, the Beauforts were barred from the royal succession. This did not stop the house of Lancaster from parading the future Henry VII as the leading claimant to the throne after the death of Henry VI in 1471. Through the male line, Henry Tudor was produced through an affair, and later marriage, between Katherine of Valois (1401-1437), the widow of King Henry V, and an obscure Welsh squire named Owen Tudor (c. 1400-1461). Their marriage, in turn, produced both Jasper Tudor (c. 1435-1495) and Henry VII's father, Edmund Tudor (1431-1456), who would die before his son was born. In 1485, as a Lancastrian claimant, Henry Tudor returned from his lengthy exile in Brittainy to defeat King Richard III at the Battle of Bosworth Field and have himself crowned as Henry VII. With the defeat and death of Richard III, the house of York and the house of Plantagenet (the latter of which had ruled over England since 1154) were officially deposed from England's throne. Remaining members of the house of York were slowly annihilated during the reigns of Henry VII and his son.
Henry VII's eldest son, Prince Arthur, predeceased him. He was therefore succeeded by his younger son, Henry VIII (r. 1509-1547) upon his death. Henry VIII would prove to be a powerful but erratic leader. He separated England from the pope when he could not attain a divorce from his first wife Catherine of Aragon (1485-1536) and began the movement which would become the Protestant Reformation. The king's reason for the divorce was because Catherine could not give him a male heir and the grounds for divorce came in the fact that Catherine had originally been married to Prince Arthur. By the end of his reign, Henry VIII would marry six times, producing only one male heir, who succeeded him as King Edward VI (r. 1547-1553). Edward VI, son of Henry VIII's third wife, Jane Seymour (1508-1537), came to the throne at the age of nine and died, six years later, aged fifteen, after a conflict filled reign (as is the case with many minority reigns). When Edward VI lay dying, he settled the succession on his cousin, Jane Grey (1536-1554), a descendant of Henry VIII's younger sister Mary (1496-1533), over his two half-sisters. Edward, a devout protestant, did not want his catholic sister Mary (daughter of Catherine of Aragon) to become queen and undo all the work towards protestantism that had been accomplished in his reign. However, once Edward VI died, the people of England rallied for Mary and Jane was only able to reign as queen for nine days. Mary was crowned as Queen Mary I (r. 1553-1558) and had a fairly short, disastrous reign, that saw her burn hundreds of protestants for their refusal to convert to the old faith. No children were produced from her marriage to Philip of Spain and she was succeeded by her younger sister Elizabeth I (r. 1558-1603), the daughter of Henry VIII's second wife, Anne Boleyn (1500-1536). Although Elizabeth would carry on the Tudor dynasty for another forty-five years, she would never marry and would not even name an heir until her last breath. She was succeeded by James VI of Scotland (r. 1603-1625), a descendant of Henry VIII's elder sister Margaret (1489-1541), who reigned as James I. Thus, the house of Stuart was seated on England's throne.