Definition of "Ellen"

And how doth my cousin, your bedfellow? and your fairest daughter and mine, my god-daughter Ellen?

c. 1596–1599 (date written), William Shakespeare, “The Second Part of Henry the Fourth, […]”, in Mr. William Shakespeares Comedies, Histories, & Tragedies […] (First Folio), London: […] Isaac Iaggard, and Ed[ward] Blount, published 1623, [Act III, scene iv]

"Is her name Ellen or Helen, Miss Viner? I thought - "Miss Viner closed her eyes."I can sound my h's, dear, as well as anyone, but Helen is not a suitable name for a servant. I don't know what the mothers in the lower classes are coming to nowadays."

1928, Agatha Christie, The Mystery of the Blue Train