“Caesar had his Brutus, Charles the First his Cromwell; and George the Third — ["Treason!" cried the Speaker] — may profit by their example. If this be treason, make the most of it.”

Speech on the Stamp Act, Virginia House of Burgesses (29 May 1765), according to John Burk in The History of Virginia: From Its First Settlement to the Present Day (Dickson & Pescud, 1805), Volume 3, p. 309. The only contemporary account, written by an unknown French traveler, tells it differently:
Shortly after I Came in one of the members stood up and said he had read that in former times tarquin and Julus had their Brutus, Charles had his Cromwell, and he Did not Doubt but some good american would stand up, in favour of his Country, but (says he) in a more moderate manner, and was going to Continue, when the speaker of the house rose and Said, he, the last that stood up had spoke traison, and was sorey to see that not one of the members of the house was loyal Enough to stop him, before he had gone so far. upon which the Same member stood up again (his name is henery) and said that if he had afronted the speaker, or the house, he was ready to ask pardon, and he would shew his loyalty to his majesty King G. the third, at the Expence of the last Drop of his blood, but what he had said must be atributed to the Interest of his Countrys Dying liberty which he had at heart, and the heat of passion might have lead him to have said something more than he intended, but, again, if he said any thing wrong, he beged the speaker and the houses pardon. some other Members stood up and backed him, on which that afaire was droped.
Edmond Randolph gave a different alternate in his manuscript history of Virginia:
In his harangue, he [Henry] certainly indulged a strain never before heard in the royal Capitol. This circumstance passed while he was speaking: “Caesar,” cried he, “had his Brutus; Charles the first his Cromwell; and George the third—” “Treason, sir,” exclaimed the Speaker, to which Henry instantly replied, “and George the third, may he never have either.”
1760s, Speech on the Stamp Act (1765)