Episode 12 of The Trigan Empire
The Reign of Thara
aka Battle for Trigan City
De slag om Trigopolis (Dutch title)
The Battle of Trigopolis (Dutch title, translated)
The Reign of Thara was originally published in 19 installments in issues 298 (30 September 1967) to 316 (3 February 1968) of Look and Learn magazine.