On 31 March 1565, the English ambassador in Scotland reported to the former English ambassador in France an incident that had (probably) occurred at Hampton Court. He had heard it from the Earl of Atholl, a grandee at the court of Mary Queen of Scots. Thomas Randolph, the ambassador in Edinburgh, described a scene between the Earl of Leicester, Elizabeth I, and the Duke of Norfolk:
That early the Duke’s grace and my lord of Leicester were playing at tennis, the Queen beholding of them, and my Lord Robert being hot and sweating took the Queen’s napkin out of her hand and wiped his face, which the duke seeing said that he was too saucy, and swore that he would lay his racket upon his face; whereup rose a great trouble and the Queen offended sore with the Duke.
Thomas Howard, 4th Duke of Norfolk. He has got a handkerchief in his purse.
Since a nobleman in Scotland had told him what had happened in an English tennis court (as opposed to a courier from England), Randolph concluded that “What is most secret among you is so soon at this Queen’s ears, that some would think it should be out of the Privy Chamber door where you are.”
Robert Dudley, Earl of Leicester. He has the same kind of purse hanging from his belt as Norfolk, with handkerchief.
In fact, nothing about this incident has survived in any other source than Randolph’s letter to Throckmorton (who was at that time at the English court). Still, this story has often been cited as evidence of both Elizabeth’s intimacy with Dudley and Norfolk’s enmity with him (although they were friends enough to play tennis). Leicester also stayed at Norfolk’s house in 1567 and Norfolk came upon him while Leicester was fishing in the Thames in 1569.
Sir Nicholas Throckmorton, with purse and handkerchief
Sources:
Kendall, Alan (1980): Robert Dudley, Earl of Leicester. Cassell.
Williams, Neville (1964): Thomas Howard, Fourth Duke of Norfolk. Barrie & Rockliff.
All Things Robert Dudley 
It’s so difficult for historians to unravel fact from hearsay or propaganda in these accounts!
Well, it may be true … 😀
The tale may be an invention, it may be true, or – like so many stories passed along the gossip networks (then and now) – it may have grown in the telling. Hardly evidence of anything, really, other than that people were talking about Dudley and Elizabeth.