Ok, so I'm far from an expert in this time period, nor am I the best writer(I know more about the 16th century), but here is my proposed overview of Elizabeth of York's reign and marriage to Jasper Tudor:
Aftermath of Henry Tudor's death
Upon hearing of his nephew's death of the sweat, Jasper Tudor was devastated, he had been the closest thing to a father the boy had ever had, and Henry had been more of a son to him than a nephew. Still, he vowed to honor his nephew's memory by taking up the Lancastrian cause himself and by uniting the Lancastrian and Yorkist factions in the most fitting way possible... Thus, soon after Henry's death, he proposed marriage to Elizabeth of York and promised that he would make her Queen in her own right, while he would be the King Consort. It was said that Elizabeth, while hesitant to marry a man older than her own mother, agreed as she believed it would be her best chance of solidifying her rule.
The two moved very quickly, Jasper and his allies arranged for a swift wedding, and then coronation at Westminster Abbey, with several prominent priests witnessing the wedding(Which took place on November 7th) so that no one could easily waylay Elizabeth and force her to marry them. Shortly thereafter the act of Titulus Regius was repealed, and Elizabeth of York was announced rightful Queen of England in her own right.
Reign
Upon her coronation, Elizabeth of York, now Queen Elizabeth I, knew she had to be vigilant, for, even with Lancastrian support, as well as the support of Yorkists that had opposed her uncle Richard III, there were still several looming threats to her rule. The first and foremost was her young cousin, Edward Plantagenet, the 17th Earl of Warwick, for while he was just a child, he was the only living legitimate Plantagenet male. As a result, she acted quickly, and gave him an ultimatum, he would be able to keep his lands, and his life, if he swore loyalty to her, and would not make any marriages or alliances that she did not approve of. The young boy, perhaps terrified, accepted, and to be safe, Edward and his sister Margaret became wards of King Jasper. The two, in spite of the fact that their marriage had taken place over political concerns, seemed to love each other deeply in spite of the age difference, and Jasper would play a key role in modernizing the Royal Army and adding more ships to the Royal Navy. In regards to her many younger sisters, Elizabeth would arrange fabulous matches for several of them: most notably for Cecily of York and Anne of York, who would both become Holy Roman Empresses through their marriages, with Cecily marrying Maximillian I as his second wife, and Anne marrying Phillip of Burgundy, who would later become Phillip I, Holy Roman Emperor. Her penultimate sister, Catherine of York would later become Queen of Scotland through her marriage to King James IV of Scotland as well. After the deal with Warwick, the remainder of Queen Elizabeth the first's thirty-five-year reign was mostly peaceful and prosperous, with the only internal rebellion being from her cousin, Edward Stafford, the third Duke of Buckingham, who rose up to press his claim on the throne via his descent from Edward III in the year 1502. He was unable to amass much support against the popular queen, and she personally lead her much larger army to crush that of the would-be usurper, who was attained and beheaded shortly after his defeat on May 27th... Though she was heartbroken by her husband's death from Pneumonia in 1495, Elizabeth would spend the rest of her reign ensuring that England would become one of the most prosperous nations in Western Europe, and in 1505, sponsored the creation of a colony at Newfoundland, laying the foundations for English colonization in North America. She would ultimately die of natural causes at the age of fifty-four on June 12th, 1520, and would be succeeded by her eldest son Arthur.
Family Tree
Queen Elizabeth I of England,(b.1466, d.1520, r. from 1485) m.King Jasper I of England(b.1431, d.1495) had issue
1)Arthur, Prince of Wales(b.1486) m.Catherine of Aragon(b.1485) had issue
2)Prince Edward, Duke of York(b.1487)
3)Prince Henry, Duke of Bedford(b.1488, d.1488)
4)Princess Elizabeth of England(b.1490)
5)Princess Cecily of England(b.1491)
6)Prince George, Duke of Bedford (b.1493)
7)Princess Mary of England(b.1494, d.1494)
8)Prince Edmund, Duke of Somerset(b.1496, posthumous son of Jasper)
King Arthur I of England(b.1486) m. Catherine of Aragon, Queen of England(b.1485) had issue
1)Princess Mary of England, Queen of Spain(b.1501)m. Miguel, Prince of Portugal, Asturias, and Girona(b.1498)
2)Stillborn daughter(1503)
3)Jasper, Prince of Wales(b.1505)m.Catherine of Austria(b.1507)
4)Princess Elizabeth(b.1507, d.1507)
5)Prince John, Duke of Richmond (b.1509, d.1509)
6)Prince Henry, Duke of Richmond (b.1512)
7)Stillborn son(1513)
8)Prince Edward, Duke of Exeter (b.1516)