Definition of "Jon"

In that Summer of 1909 the simple souls who even then desired to simplify the English tongue, had, of course, no cognizance of little Jon, or they would have claimed him for a disciple. But one can be too simple in this life, for his real name was Jolyon, and his living father and dead half-brother had usurped of old the other shortenings, Jo and Jolly. As a fact little Jon had done his best to conform to convention and spell himself first Jhon, then John; not till his father had explained the sheer necessity, had he spelled his name Jon.

1920 October, John Galsworthy, Awakening, New York, N.Y.: Charles Scribner’s Sons, page 6

"I suppose I ought to call you Uncle Jack now." "Please don't. My name is Jonathan, and I've never had a nickname. Doesn't go with my character. So, Uncle Jon - if you must."

1994, Robertson Davies, The Cunning Man, Viking, published 1995, page 16