The most legendary military campaign executed by the Crimson Fists Chapter of Space Marines was the Crusade of Righteous Liberation, conducted for three hundred standard years during the 36th Millenium before the Crimson Fists had given up their original role as a Fleet-Based Chapter and settled on their homeworld of Rynn's World.
At this time, known to Imperial savants as the Age of Apostasy, the Imperium was wracked by internal strife and physically disrupted by swirling Warp Storms as a result of the Emperor of Mankind's displeasure. Much of the turmoil arose from a massive schism within the religious organisation of the Adeptus Ministorum of Terra.
After the arch-traitor High Lord Goge Vandire was finally slain by his own bodyguards, the Daughters of the Emperor who eventually became the Sisters of Battle, the Crimson Fists Chapter took it upon themselves to wrest back control of Imperial worlds that had fallen from the Emperor's grace. The whole Chapter's fleet of Battle Barges and Strike Cruisers forced its way through the Warp Storms to liberate those planets which had fallen into anarchy or been invaded by alien races.
The first such world they came across was Welte, which they found subjugated by the Ork Warlord Ghar Nazzghar -- loathed by many at the time as the brutal Plunderer of Polemis. A force drawn from 4 different Crimson Fists companies descended upon Welte, whilst the rest of the Chapter fleet dropped back into the Warp to locate other such stricken worlds.
Led by the valiant Captain Sandriaz, the Crimson Fists fell upon Ghar Nazzghar like an azure-armoured storm. They struck at his ore mines, burnt the human slave factories and wrecked the ramshackle convoys that transported food and weapons across Welte's treacherous dust bowls. Ghar Nazzghar's Orks soon found themselves scattered across much of the world trying to protect the few installations that still remained.
It was then that Captain Sandriaz mustered his force once more and attacked Nazzghar's stronghold in the ruins of what was once Welte Prime, the world's capital city. With most of his warbands chasing ghosts across the dust bowls, Ghar Nazzghar could do nothing as the mighty Astartes advanced relentlessly through the shattered town.
Nazzghar himself led a final counter-attack, but he and his cadre of burly Ork Nobs were wiped out as they ran the gauntlet of the Crimson Fists' concentrated fire. With Ghar Nazzghar dead, the Crimson Fists left Welte, leaving the fragmented Orks to the surviving Imperial citizens who had been so brutally enslaved and repressed during the Greenskins' rule.
Welte was just the first of 84 worlds re-conquered by the Crimson Fists during the Crusade of Righteous Liberation. Over the Crusade's 300 Terran-year-span, the Chapter's numbers dwindled through age and battle losses; whilst crusading, the Crimson Fists were unable to recruit new Initiates to replace their losses. Finally, after breaking the four-century-long rebel siege of Barenthal on Excelsiva II, then-Chapter Master Kordova declared the Crusade of Righteous Liberation to have ended.
Only 128 Crimson Fists were left and ever since then, the numbers of the Chapter's 1st Company has always been kept at 128 Astartes in memory of this time, and it's Captain is also always the Crimson Fists' Chapter Master. The 1st Company is always known amongst the Crimson Fists as the Crusade Company, and it is considered a bad omen if the Chapter goes to war without the Crusade Company being at full strength.
- White Dwarf 287 (US), "Index Astartes: Bloodied Fist - The Crimson Fists Space Marine Chapter"