Pacification of Persepolis

The Pacification of Persepolis was the first recorded Imperial campaign undertaken by the newly created Sable Lions Space Marine Chapter against the Forces of Chaos comprised of Heretic Astartes from both the Night Lords and Word Bearers Traitor Legions upon the isolated desert world of Persepolis.

History
Following their creation, the Sable Lions Chapter were granted the primitive Desert World of Persepolis and its surrounding system as their demesne. Upon arrival, the Chapter's Librarians immediately detected the unmistakable taint of Chaos. Following a scan of the surface, the Sable Lions quickly determined that the planet was under attack by a large force of Chaos Space Marines comprised of the Night Lords and Word Bearers Traitor Legions, massed cult-hordes and waves of daemons. They attacked the planet's populated walled-cities, committing genocide on a massive scale. Seething with rage, the Sable Lions launched a planetary assault, deploying their entire Chapter to the planet's surface. Though many of the planet's cities were reduced to ruin, after many months of brutal and bloody fighting, the Sable Lions emerged bloodied but victorious, breaking the back of the Chaos forces, and forcing them into shameful retreat. In gratitude, the grateful populace built the Sable Lions' fortress-monastery, Haydar al-qasr (the "Lionhold") amongst the world's tallest mountains, the Asad Asnaan.