After decades of civil war, England's Wars of the Roses came to an end with Henry Tudor defeating Richard III at Bosworth Field in 1485. Henry, now Henry VII, dedicated his reign to securing the throne of England. He married Elizabeth of York, tying together the Lancasters and the Yorks to end the matter of supremacy and defeated anyone who continued to rebel. Henry also encouraged support from Wales by claiming Welsh descent. Most of all, he sought European recognition, which would legitimize his rule despite his being a questionable heir. Treaties ended war with France and called for Perpetual Peace with Scotland. He looked to the newly unified kingdoms of Castile and Aragon whose Ferdinand and Isabella were successfully driving the Moors out of Spain. In 1489, England and the Catholic Nobles signed the Treaty of Medina del Campo. Ferdinand and Isabella's youngest daughter, Catherine, would marry Henry's oldest son, Arthur.
Arthur had been born September 20, 1486. His father had prophesied that Elizabeth's child would be a boy, whom he would name Arthur as he would bring about a new golden age for England. Henry arranged for the birth to be held at the capital, Winchester, which proved a bold and successful move. Arthur was estimated to be born prematurely but was strong. He was betrothed before his third birthday to Catherine, a few months older than he. Soon he was created Prince of Wales, coinciding with the birth of his sister Margaret, who would marry James IV of Scotland and secure England's northern border. Arthur grew up at Ludlow Castle in Wales under the guidance of tutors expert in politics, humanism, and science. Bernard André, the blind poet and biographer, ensured he thoroughly read the Greek and Latin Classics.
During his education, Arthur wrote letters to Catherine in formal, polite Latin, and she replied in kind. Arthur was quiet and reflective, much unlike his younger brother Henry, who preferred jousting to his clerical studies. After they were married in proxy in 1499, Arthur wrote to Ferdinand and Isabella that he would be "a true and loving husband" to Catherine. The two finally met and were married in November of 1501; Arthur said to his parents that he was pleased to "behold the face of [my] lovely bride." Despite his reservedness, Arthur commented to others before his wedding that that we was "lusty and amorous" and after, "Masters, it is a good pastime to have a wife."
The couple retired to Ludlow Castle, where Arthur continued his duties as Prince of Wales. A plague of "sweating sickness" struck the castle, including the royal couple. After a harrowing illness, Arthur pulled through, saying he owed much to the dutiful care of his wife. They had their first son, Edward, three years later. Henry VII, seeing that his line was continued, died at peace in 1509. Arthur's brother Henry, meanwhile, settled into his role in the Church, where he convinced his brother to pull away from Roman authority as the Catholic monarchs had done with their own Spanish Inquisition. The English Inquisition, while never granted great powers, served as a significant contributor to military science following Henry's creative interests.
The action caused war with Catholic Spain during the reign of Edward's eldest son, Henry VIII. The two nations fought their wars abroad, not risking the investment of direct invasion by an armada. Civil war in Scotland in 1638 against its king Charles sparked invasion by the English to defend Protestant interests. Success there prompted England to contribute to the Eighty and Thirty Years' Wars on the Continent, but the expense proved too great and resulted in the loss of Scotland as well as Catholic Ireland by the beginning of the 1700s. After recuperating, England returned her attention to colonies abroad, carving out a massive empire in North America (between Scottish Canada, French Louisiana, and Spanish Mexico), India, and Africa, but always seemingly at a shortage of manpower.
As an end came to Colonialism, England reinvented her colonies into the Commonwealth, which proved to be a potent economic and defense network. Other colonial nations, such as the Netherlands, Portugal, and Scotland, whose advancements in industrial technology in the late 1700s brought it among world leaders, lost much of their clout as the empires became fully independent.
In reality, Arthur died of unknown causes at the age of 15. Henry VIII succeeded his father, whose dying wish it was for him to marry Catherine despite protests by the Pope and the prince himself to ensure a male heir. The marriage ultimately failed as only one of Catherine's six children from 1510 to 1518 lived beyond a few weeks: Mary I of England. Henry annulled the marriage, breaking with Rome when the Pope refused. Five marriages and several heirs later, his daughter Elizabeth I had no issue, prompting the throne to be given to James VI of Scotland, unifying Britain.