Prince Hagen

From Author Wars - https://authorwars.com/publications/prince-hagen-418239.html

Overview:

Title: Prince Hagen
Author: Upton Sinclair
Year: 2002
Publisher: Project Gutenberg
Price: $0.00
Binding: ebook
Type: Novel
Title Reference: Prince Hagen
Notes:
The content is Sinclair's 1909 stage adaptation of his 1903 novel, as revised and privately printed for distribution to theaters, probably in 1909. As of April 2019 Project Gutenberg has not released an edition of the 1903 novel Prince Hagen: A Phantasy (where again it might use the short title).

Project Gutenberg does not identify the source text, nor report a year, nor a publisher or printer. The ebook does not contain a title page transcript.

One candidate source text is Plays of Protest, a collection of four plays, in its 1912 first edition (see at ISFDB). Comparison with the 1st ed. collection (viewed at HathiTrust) shows that it may be the source for all of Project Gutenberg Ebooks #3301 to 3304, although their sequence does not match the collection, where Prince Hagen is the last of four.