In the opening night version of The Rivals, Lucius O'trigger's reason for dueling was Lydia, but then Sheridan changed it to an ensign's casting aspersions on Ireland.

An introductory essay in the Barrons Educational Series version of the play says:

"A critic for The Monthly Miscellany for February 1775 summarizes the original performance as follows:

It's present state is widely different from that in which it appeared on the first night's representation. Sir Lucius O'trigger, being retouched, has now the appearance of a character; and his assigning Beverley's reflection on his country, as the grounds for his desire to quarrel with him, is a reasonable pretence, and wipes off the former stigma underservedly thrown on the sister kingdom."

Further along, the essay goes on to say:

"A greater piece of miscasting seems to have been that of Mr. Lee as Sir Lucius (he was succeeded by the eminently satisfactory Laurence Clinch in the second version); Lee was denounced equally by audience and critics. Whether "so villainous a portrait of any Irish gentleman" was to be attributed mainly to Lee's performance or Sheridan's text has been and is argued; apparently it was an involuntary collaboration...the audience felt that the part was a savage caricature of the Irish gentleman. Presumably it was at least in part Sheridan's fault, for his original text presented a Sir Lucius who was unsympathetic. He was obvious, if not coarse; he was occasionally silly; and he was also a transparent marital adventurer, for although young and personable,..."

It goes on to talk about Lee's awful acting and unbelievable Irish accent, then continues:

"...Besides suppression, Sheridan carefully introduced such lines as those given to Lucy, who speaking of Sir Lucius says, "...he had too much pride and delicacy to sacrifice the feelings of a gentleman to the necessities of his fortune." This reversal of the original character evidently averted an international crisis at the time."

Summarizing more of the essay: