Because land was equivalent to power in the 1400's, powerful men could try to claim the English crown. This led to the conflicts known as the Wars of the Roses, battles for power fought between the house of York, the white rose, and the house of Lancaster, the red rose. The turmoil was at its peak during the reign of Henry VI (Lancaster) because of his personal weaknesses and mental instability. Although the fighting was very irregular, the result was a general breakdown in the authority and power of the Crown. His son who later became Henry VII united the two houses by marrying Elizabeth of York and combining red and white to give what is now known as the English Rose.

A
Henry VII
The Wars of the Roses culminated in the eventual victory of the relatively unknown Henry Tudor, Henry VII, at the Battle of Bosworth Field in 1485, where Richard III of York was killed, and Henry Tudor of Lancaster became King. But before the end of his reign, two pretenders had tried to dethrone him, helped by supporters of the house of York, both unsuccessfully. The first, Lambert Simnel, was defeated in battle; the second, Perkin Warbeck, was hanged in 1499.
In 1497 Henry was challenged again, Michael An Gof led Cornish rebels in a march on London. He fought for various issues mainly rooted in taxes. On June 17, 1497, he was defeated, and Henry VII showed he could still display military prowess when he needed to. The rest of his reign was relatively peaceful, despite a slight worry over the succession when his wife Elizabeth of York died in 1503.

B
Henry VIII
During his colourful reign Henry VIII split with the Roman Catholic Church over the question of his divorce from his 1st wife Catherine of Aragon. Though his religious position was not at all Protestant, the resultant split ultimately led to England distancing itself almost entirely from Rome. There followed a period of great religious and political unrest which led to the English Reformation: The seizure of the monasteries and much of the wealth of the church by the King. The break up of the monasteries had the effect of giving many of the lower classes an interest in the Reformation continuing, because to halt it would restore lands which were given to them during the breakup to the monasteries.
Henry VIII only had one legitimate child, from his first marriage to Catherine of Aragon. He also fathered two illegitimate children from his second and third wives. And after the death of his third wife Anne Boleyn he remarried a further three times. Two lucky wives were divorced, the mother of his son died during childbirth, two of his wives were beheaded and his final wife, Catherine Parr, outlived him.

C
Edward VI
The first of Henry's children to reign was Edward. Although he showed some intelligence, he was only 10 years old when he took the throne in 1547. His uncle, Edward Seymour, interfered with Henry VIII's will and obtained letters giving him much of the power of a monarch when he took the title of Protector. Whilst some saw him as an idealist, his stay in power ended in crisis in 1549 when many of the counties protested. Lord President Northumberland then proceeded to adopt the power for himself. When Edward VI lay dying of tuberculosis in 1553 at the age of 16, Northumberland made plans to place Lady Jane Grey on the throne and marry her to his son, so that he could remain the power behind the throne. His putsch failed and Lady Jane suffered the same fate as Henry's second and fourth wives.

D
Mary I
Mary I, Henry's only legitimate child, took the English throne in 1553. She was a devout Catholic who had been influenced greatly by the Catholic King of Spain and Holy Roman Emperor, Charles V. She tried to force Catholicism back on the people of England. This led to 274 burnings of Protestants, making her highly unpopular among her people. The Spanish party of her husband, Philip II, also caused much resentment around court. Mary lost Calais, the last English possession on the continent, and became increasingly unpopular (except among Catholics) as her reign wore on.

E
Elizabeth
Elizabeth restored a sort of order following the turbulence of the reigns of Edward and Mary when she came to the throne following the death of Mary in 1558. The religious issue which had divided the country since Henry VIII was put to rest by the creation of the Church of England. Much of Elizabeth's success came from balancing the interests of Puritans and Catholics. Elizabeth maintained relative government stability and was effective in reducing the power of the old nobility and expanding the power of her government. During the reign of Elizabeth and shortly afterward, the population of England grew significantly: from three million in 1564 to nearly five million in 1616.
In all, the Tudor period is seen as a decisive one which set up many important questions which would have to be answered in the next century and during the English Civil War. These were questions of the relative power of the monarch and Parliament and to what extent one should control the other.