As a young man, Arthas was heir to the House of Liktor.
During the close of the Four Years War between the Federation and the Klingon Empire, Starfleet occupied those Orion Colonies formerly held by the Klingons, in a period Orions knew as the Year of Horror. Among those worlds was Hartha. There the Federation placed restrictions on commerce that the Orions found intolerable. These new rules were supported by a military presence that the Orions could not resist.
In response, in reference stardate 1/9805 (c. 2256), Arthas Liktor ran through the Federation front lines aboard a modified courier ship, and made it to the Orion homeworld of Botchok (Rigel VIII). He attempted to warn of the tightening Federation grasp, but the Botchok Planetary Congress was worried about the Federation's intentions. Arthas and his crew were imprisoned to stop them talking. (FASA RPG module: The Orions: Book of Deep Knowledge)