He speaks only in the first act, and has a total of eighteen lines. Of course, this reflects the importance of the real man. Lord Abergavenny is linked to, in Wikipedia, to George Nevill, 5th Baron Bergavenny.

George didn't do much in the way of affecting the storyline of Henry's life, though his younger brother, Sir Edward Nevill, did get executed by the King in 1540. Edward was supposed to have been planning to promote Reginald Pole, who was the enemy of the king. This is probably understandable on Edward's part, as the Nevill brothers had Nevill sisters, one of whom, Jane, was married to one of the Pole brothers, namely Henry, the elder of the Poles and also the 1st Baron Montagu.

The Nevills were born in Norfolk, England, to the 4th Baron Bergavenny. Our Nevill, the one that Lord Abergavenny made famous, was born to the second of three wives and succeeded by the second of his three wives. All in all, his life isn't very well searchable on the internet, and if it weren't for the dear Poet, we would probably forget about him entirely, and even then, sadly, Mr Nevill isn't really the most important person in the play.

Oh, and in case you wanted to know why I care... My dear old Dell is named after this minor character. So round of applause for Lord Abergavenny, on and off stage!