“BALTHAZAR: I have a private coat for Italian stilettos, I can be treacherous with the Walloon, drunk with the Dutch, a chimney-sweeper with the Irish, a gentleman with the Welsh and true arrant thief with the English. What then is my country to me?”

First ascribed to Wilde by The Boston Globe in 1991. The joke probably appeared for the first time in 1917, when The Atchison Weekly Globe attributed it to a local man named Frank Fiest.
Misattributed
Source: My Idea of a Gentleman Is He Who Can Play a Cornet and Won’t, Quote Investigator, 14 August 2021 https://quoteinvestigator.com/2019/04/21/cornet/,

Letter to Sir William Spring (September 1643)

Source: Prajwal Hegde "I am enjoying my partnership with Cara Black: Sania Mirza"

Lord Illingworth, Act I
A Woman of No Importance (1893)

On pleasure.
What It Is (2009)

Comment on Benito Mussolini in 1933, as quoted in Three New Deals : Reflections on Roosevelt's America, Mussolini's Italy, and Hitler's Germany, 1933-1939 (2006) by Wolfgang Schivelbusch, p. 31
1930s

2000s, Speech at the Republican National Convention (31 August 2004)

The Liberty of Man, Woman and Child (1877)
Context: Standing in the presence of the Unknown, all have the same right to think, and all are equally interested in the great questions of origin and destiny. All I claim, all I plead for, is liberty of thought and expression. That is all. I do not pretend to tell what is absolutely true, but what I think is true. I do not pretend to tell all the truth.
I do not claim that I have floated level with the heights of thought, or that I have descended to the very depths of things. I simply claim that what ideas I have, I have a right to express; and that any man who denies that right to me is an intellectual thief and robber. That is all.

Source: The Hunger Angel (2012), p. 4