Edward's first marriage was arranged by his father Henry III and Alfonso X of Castile to marry the daughter of Alfonzo, Eleanor who was 13 years of age. He was 15 years of age when he crossed the channel, Alfonzo kighted him as he had previously requested of King Henry III. Grants of land worth 15,000 marks a year were to be given to Edward. Edward and Eleanor were married on 1 Nov 1254 in the Las Hueglas Monastery in Castile, France. They had 16 children of whom 10 died shortly after birth or before reaching adulthood.
(Sources differ on the age of Eleanor. Some say she was only 9 years of age.)

Eleanor died in 1290 which left Edward deep in grief. He display his grief by erecting a cross at each place where the funeral cortege stopped for the night. These crosses were called the 'Eleanor Crosses'.

At the age of 60, Edward married Marguerite of France on 10 Sep 1299. She was 20 years old and the daughter of King Philip III of France and Maria of Brabant. Three Children were born to them.

Edward leaned many lessons from the failures of his father, Henry III as king, while growing up.. His character contrasted with his father who tended to favour compromise with his opponents. Edward was an ambitious and impatient man.

He fought in a civil war to defend his father. Expense in the intervention in Sicillian affairs was grossly misjudged, which caused powerful barons to become angry with him. Simon De Montfort, his brother in law was one of the Barons. Henry III was bankrupt and he was threatened with excommunication. The problems with his father's decision making caused Edward to eventually become Simon De Montfort's enemy. After winning the battle of Lewes in 1264, Edward became a hostage to ensure his father would abide by the terms of peace. He was put in prison ate Wallingfor Castle and Kenilworth Castle by De Montfort.

Edward escaped in May 1265 while on a hunting trip. He showed what a great military he could be when he defeated Simon De Montfort. In a Savage battle at Evesham, he and his allies defeated De Montfort. where De Montfort himself predicted his own defeat and death by saying, "Let us commend our souls to God, because our bodies are theirs.....They are approaching wisely, they learned this from me."

Edward treated rebels and other foes savagely and relentlessly pursued De Montfort's surviving family and cousins. The Civil War ended and Edward worked for social and policial reconcilitation between his father and the rebels and the realm had been padified by 1267.

In 1270, at the urging of Louis IX, parliament financed Edward's Eighth Crusade to the Holy Lands. He left in August 1270 with his wife and between 230 & 1,000 knights (historians don't agree) and joined the French King Louis IX. During this time the crusades were used to further the political ends of the popes. His crusade was rather insignificant and only gave the city of Acre a reprieve of ten years. Edward's reputation, however, was enhanced greatly by his participation in the crusades.

King Edward refused to recognize the Treaty of Montgomery, 1267 with Wales. Llywelyn ap Gruffyd had extended the territories of Wales south into lands of English Marcher Lords and he became the Prince of Wales. He still had to pay homage to the monarchs of England. In 1275, King Edward paid pirates to intercept a ship on which Eleanor de Montfort was aboard. She expected to Marry Llywellyn. Edward imprisoned her at Windsor. Llywelyn then refused to pay homage to Edward at which time Edward gathered an army launced an attack against the Welsh prince. Llywelyn was stripped of all but a small part of Gwynedd. However, Edward allowed Llywelyn to keep his title of Prince of Wales. After a rebellion in 1282 by Daffyd, brother of Llywelyn, which was quickly put down by Edward when he captured him, tortured and put him to death thus subduing Wales.

In 1307 Edward planned to conquer Scotland.who were under the leadership of Robert The Bruce. While on his way to begin the campaign against the Scots he died at Burgh-by-Sands, Cumberland on the Scottish border.