about Leonardo da Vinci...

...Then the king, who used often and lovingly to visit him, came in, and he, raising himself respectfully to sit up in bed, spoke of his sickness,

and how he had offended God and man by not working at his art as he ought.

Then there came a paroxysm, a forerunner of death, and the king raised him and lifted his head to help him and lessen the pain, whereupon his spirit, knowing it could have no greater honor, passed away in the king's arms in the seventy-fifth year of his age.

From Giorgio Vasari: "Life of Leonardo da Vinci", in Lives of the Most Eminent Painters, Sculptors, and Architects

Often this is mis-constructed to be Da Vinci's last words -

I have offended God and mankind because my work did not reach the quality it should have." (eg. here)