Some closing wit of Thomas More on his way to execution. This has been mangled into several versions over the years so I’m giving what I believe is the original – from The Life of Sir Thomas More by his son-in-law William Roper:
And so was he brought by Mr. Lieutenant out of the Tower, and from thence led towards the place of execution, where going up the scaffold, which was so weak that it was ready to fall, he said to Mr. Lieutenant, “I pray you, I pray you, Mr. Lieutenant, see me safe up, and for my coming down let me shift for myself.”
I still think Paolo Sarpi’s Agnosco stylum Curiae Romanae wins for quality, but I doubt it was as impromptu.