Stephen and Matilda were two key figures in the civil war that took place in England from 1139 to 1153, known as the Anarchy. This conflict was characterized by a struggle for the English throne between Stephen, who had seized the crown in 1135 upon the death of his uncle, King Henry I, and Matilda, the daughter of Henry I and the rightful heir to the throne according to the rules of primogeniture.
The conflict between Stephen and Matilda began almost immediately after Henry I's death. Matilda, who was living in Anjou, France at the time, was supported by her half-brother, Robert of Gloucester, and her uncle, King David I of Scotland, while Stephen was supported by a number of influential English barons.
Stephen's hold on the throne was tenuous at best, as many of the English nobles were unhappy with his rule and believed that Matilda had a stronger claim to the throne. As a result, the country was plunged into a state of civil war, with each side fighting for control of key castles and cities.
The war was marked by a series of military campaigns and battles, with both Stephen and Matilda gaining and losing ground at various points. One of the key turning points in the conflict came in 1141, when Matilda's forces were defeated at the Battle of Lincoln, leading to her capture and imprisonment.
Despite this setback, Matilda's supporters continued to fight on, and in 1153, Stephen was finally forced to agree to the Treaty of Winchester, which recognized Matilda's son, Henry, as the rightful heir to the throne. Stephen retained the crown for the remainder of his life, but upon his death in 1154, Henry was crowned King Henry II, bringing an end to the Anarchy and the civil war between Stephen and Matilda.
Overall, the civil war between Stephen and Matilda had a significant impact on the course of English history, as it led to a period of political instability and weakened the power of the monarchy. It also paved the way for the rise of the Plantagenet dynasty, which would go on to rule England for over 300 years.