Robin Hood is one of England's most enduring legends, but the truth behind the myth has long been lost. Historians believe that Robin Hood existed, but exactly who he was remains a mystery. Some say he was the aristocrat Robin of Locksley. Popular stories have Robin and his outlaws living in Sherwood Forest, fighting for the people in the name of Richard the Lionheart against his evil brother Prince John. He has always been portrayed as the hero who took from the rich to give to the poor.
He is known by many different names, including Robin Hood, Robin Wood, Robert Earl of Huntington, Roberd Hude, Robert Hood, and other variations. Robin Hood also exists in many forms, simply because his stories were first passed around by spoken word, in the form of folk tales and ballads dating back to the 1300's.
Robin stands as the hero of the common people and yeomans and a symbol of "right against might". Because of the Sheriff of Nottingham's tyrannical rule and exploitation of the common people in Nottinghamshire, Robin united his fellow folk and rebelled against the Sheriff. Robin is also known for "robbing the rich and giving to the poor."
Some people say that Robin is high-born, possibly even being the Earl of Huntingdon, Robert Fitzooth. Kelly Anne Hamel suggests that Robin Hood might instead have been the Earl of Locksley, who was also known as the Earl of Huntington.
"Robert Earle of Huntington
Lies under this little stone.
No archer was like him so good:
His wildnesse named him Robbin Hood.
Full thirteene yeares, and something more,
These northerne parts he vexed sore.
Such out-lawes as he and his men
May England never know agen."
When Richard the Lion Heart returned to England, only one castle of King John's didn't immediately surrender - Nottingham.
Richard I had to lay siege to the place for three days. And when he was done, he went hunting in Sherwood. And who was one of the key figures in the act on Nottingham? Why, the Earl of Huntingdon! Although he was really David, not Robin Hood."
Ancestors and-or relations of Picot DE SAI of Clun, Sheriff of Cambridge
King William sought aggressive types for the office of sheriff whose ambitions were consistent with his. Those willing to squeeze the peasants to their maximum were the best qualified in William's eyes. He instituted the practice of selling the office to the highest bidder. This brought forth evil men willing to pay exorbitant prices for the office and then willing to do whatever it took to recoup their investment. . . No one spoke out for the peasantry because their only representative to the king was the very sheriffs embezzling them.
The most notorious was Picot, Sheriff of Cambridgeshire. . . . Monks describe him as: "a hungry lion, a prowling wolf, a crafty fox, a filthy swine, a dog without shame, who stuffed his belly like an insatiable beast as though the whole country were a single corpse."
High Sheriff of Nottinghamshire, Derbyshire and the Royal Forests
1180-1186: Radulf Murdac
1187-1193 ?????? ( the sheriff we are interested in )
1194: William de Ferrers, 4th Earl of Derby (for seven weeks)
William II de Ferrers, 4th Earl of Derby (c. 1168 – c. 1247) was a favourite of King John of England. He succeeded to the estate (but not the title) upon the death of his father, William de Ferrers, 3rd Earl of Derby, at the Siege of Acre in 1190. He was head of a family which controlled a large part of Derbyshire which included an area known as Duffield Frith.
He adopted his father's allegiance to King Richard as the reigning king. On Richard's return from the Third Crusade, in the company of David Ceannmhor and the Earl of Chester he played a leading role in besieging Nottingham Castle, on the 28th March 1194, which was being held by supporters of Prince John. For seven weeks after this he held the position of Sheriff of Nottinghamshire and Derbyshire. 
Whilst Richard the Lionheart was away on the Third Crusade, and a great number of English noblemen were away with him, it was said that Nottingham Castle was left derelict and it was occupied by the Sheriff of Nottingham. In the legends of Robin Hood, Nottingham Castle is the scene of the final showdown between the Sheriff and the hero outlaw in many tales.
In 1194, a historic battle took place at Nottingham castle when the supporters of Prince John captured it. The castle was the site of a decisive siege when King Richard I, returned to England and besieged the castle with the siege machines he had used at Jerusalem. Richard was aided by Ranulph de Blondeville, 4th Earl of Chester, and David of Scotland, 8th Earl of Huntingdon.
The Sheriff of Nottingham
You may think you know the story of Robin Hood but who really was the Sheriff of Nottingham?
One possible candidate is Roger de Lacy (formerly Roger Fitz Eustace) who was the 7th Baron of Halton and Constable of Chester. His father John, the 6th Baron of Halton, was the son of Albreda de Lizours by her second marriage to Richard Fitz Eustace of Halton Castle in Cheshire
John, the king’s brother, known by the title Count John of Mortain, came to England in 1191 he became the focus for a rebellion
When Longchamp besieged Lincoln Castle to remove Gerard Camville, the Constable there, and replace him with someone more loyal, Count John retaliated by taking the unguarded castle at Nottingham. He told Longchamp that if he did not end his siege he would ‘visit him with a rod of iron and such mighty host that he could not withstand’.
The two men were squaring up for a fight when the Archbishop of Rouen, sent by the king, arrived from Messina to sort it out. He arranged a compromise: Longchamp left Lincoln and Count John gave back Nottingham. But as soon as the Archbishop left the country Longchamp tore up the agreement and entrusted the custody of the castles at Nottingham and Tickhill to Roger Fitz Eustace and gave him orders to hang the two Constables who had conspired to surrender the castles to John. In revenge, John plundered Roger’s estates including taking Pontefract Castle from him.