It is simply not possible to locate the historical Robin Hood with any certainty. The literary corpus very firmly locates the activities of the outlaw in the north, around the Barnsdale area and Sherwood Forest.
This possibly indicates that the legend as we have it already derives from two separate sources, probably two separate 'Robin Hoods'. The Scottish historian John Major, writing in 1521, maintained that Robin Hood was active in 1193-4, at the time of John's attempted coup against Richard, and it is possible to construct an argument which supports this.
On 25th July 1225, the royal justices held an assize at York. When the penalties were recorded in the Michaelmas roll of the Exchequer, they included 32s. 6d. for the chattels of one Robert Hod, fugitive. The account was carried forward into the following year, when he had acquired the nickname of 'Hobbehod', and indicates that he had been a tenant of the archbishopric of York.
This is the only possible original bearing the name of Robin Hood who is know to have been an outlaw (there are other Hoods in Wakefield, but none of them seem to have been fugitives). An epitaph recorded by Thomas Gale in 1702 recorded that a grave purporting to be that of Robin Hood lay at Kirklees (where the legend claims he was killed), dated to 1247.
On this flimsy evidence, it is possible to construct a chronology: Robin active in the 1190s, an outlaw by 1225, dead by 1247 and a legend by 1261. Quite frankly, I wouldn't stake my reputation on it. John Major's dating is purely arbitrary, and two of his contemporaries give Robin's dates as 1283-5 or 1266; while the full date on the Kirklees gravestone, 25 Kalends Decembris 1247, is impossible as there is no 25 Kalends in the Roman calendar.
The only thing to be said in favour of Major's dating is that it fits well with the only two firm pieces of evidence we have, the court rolls of 1225 and 1261. On this basis, I think we would be fully justified in saying that Robin Hood was active during the reign of King John, but that his fame and popularity were such that within a generation his true identity had been obscured by legend.
The Romance of Robin
Around these bare facts a wonderfully fanciful romance has been woven in an Anglo-French chronicle which dates to the C13th. The same is true of another historical outlaw, Eustace the Monk, who seized control of the island of Sark in 1205 and terrorised the Channel with piracy until killed at Sandwich in 1217.
Both of these interweave magical incidents and anecdotes reminiscent of the tales of Hereward the Wake; but they also contain stories which can be directly compared to some of the tales of Robin Hood. Eustace, like Robin, disguises himself as a potter in order to confound his enemies: Fulk disguises himself as a charcoal-burner. Fulk robs the king's merchants, at the king's expense, and forces them to dine with him.
Eustace pulls exactly the same trick as Robin when he asks those he waylays how much they are carrying, and lets them off if they tell the truth; and like Robin with the Sheriff of Nottingham, Fulk lures the king into the forest, where he kidnaps him, invites him to dinner and eventually lets him go. These parallels are not mere coincidences, they are exact analogies, and they share much of the same mythological basis as the earlier tales of Hereward the Wake (who himself uses disguises and trickery). If our dating of Robin Hood is correct, then the tales are contemporaneous, and what we can see here is the development of a popular mythology which eulogises those men who stood out against the excesses of John's rule.
In the reign of Henry II, the outlaw was a villain. Warin de Wolcote was a parasite on society, and Henry did everyone a favour when he marched into Sherwood Forest, dragged him to Northampton and stuck his head on the city gates. By the time of John, all this has changed.
Now the likes of Fulk fitzWarin (no relation), Eustace the Monk and Robin Hood are the gadflies of authority, who turn injustice on its head. They may not rob the rich to feed the poor, but they do beat the strong to help the weak. This explains the enduring popularity of the Robin Hood legends; they are the little man's way of striking back.