The story is told of various British monarchs. Henry VIII was the first to receive credit.
That would be some time between 1509 and 1547, although he did not receive the credit until 1655.
Next, in 1732, Jonathan Swift bestowed the credit upon James I, who reigned from 1603 to 1625. The last to be credited, in 1822, was Charles II, ruler between 1660 and 1685.
In each tale the monarch was supposed to have been so delighted with the quality of a roasted upper portion of a loin of beef, upon some special occasion, that he drew out his sword, touched the beef with it, and said, “Hereafter thou shalt be dubbed ‘Sir Loin.'”
Aside from the profusion of “dubbers,” the only trouble with the tale is that it is utterly fictitious. The only story in the word is that some time about 1600 it began to be misspelled.
For many years this cut of meat had been known as surloin, which, from sur, over or above, meant nothing more than the cut over the loin.
This correct spelling persisted, but after the foregoing stories began to be taken seriously, everyone began to shift to sirloin.