Episode 14 of The Trigan Empire
The Three Princes
aka De zonen van de keizer (Dutch title)
The Emperor’s Sons (Dutch title, translated)
A Tale of Sons and Heirs (Hawk reprint)
A Tale of a Perilous Journey (Hawk reprint)
A Tale of an Infernal Machine (Hawk reprint)
Written by Mike Butterworth
Illustrated by Don Lawrence
The Three Princes was originally published in 31 instalments in issues 332 (25 May 1968) to 362 (21 December 1968) of Look and Learn magazine.
It was reprinted in 1975 in 8 issues (25 October 1975—13 December 1975) of Vulcan comic.
It was reprinted in 1989 as A Tale of Sons & Heirs, A Tale of a Perilous Journey, A Tale of an Infernal Machine in Tales from the Trigan Empire (Hawk).
It is reprinted in Volume 4 of The Trigan Empire—The Collection (the Don Lawrence Collection).
It is reprinted in Volume 2 of The Rise and Fall of the Trigan Empire (Rebellion).
Plot summary (Dutch)
MediaFire via British Comics Compilations