.M37Chapter departs towards Imperial Borders to avoid corruption and the stigma of the 21st Founding.
543.M37 The Liberation of Aphennia.
901.M38 Chapter suffers its first ever instance of the "Red Thirst". Sepulchre Guard is formed by the Chapter leadership to watch for signs of failure in the genome. However no more instances are recorded.
.M39Chapter recalled by Highlords with other Chapters to stem flow of incursions from the Eye of Terror.
478.M39 Captain Jordanes of the Lamenters settles a century old feud with Wolf Lord Snorri Bloodmane.
603.M39 Quintus Viridian, Captain of the 7th, is gravely injured battling the Eldar on the Maiden World of Karamet. Viridian is interned in a Furioso Dreadnought.
587.M41Chapter assigned to the Maelstrom Zone.
701.M41Lamenters forces manage to inflict heavy casualties on Orks during the Corinthian Crusade, subsequently putting Waaagh-Argluk back thirty years.
843.M41 Janus Eurico is inducted into the Lamenters. He goes on to be a mighty hero of the Lamenters.
857.M41 Lamenters destroy cultists on the shrine world of Apuis III.
891.M41 Master Forsythe of the 1st Company recovers his ancient suit of Terminator armour, Patagonian, from deep within the Maelstrom.
903.M41 Forces under Chaplain Athaloc are the first to draw Loyalist blood.
904.M41Sagan Battles against Loyalist Marine forces.
905.M41 Epistolary Menoloth disappears in the Maelstrom. He is presumed lost in the warp.
906.M41 Master Roderigo of the Lamenters slays an Emissary from the Red Scorpions Chapter who attempted parlay.
908.M41Lamenters forces are attacked by the Minotaurs and surrender after tough and bloody ship-to-ship fighting. Chapter Master Malakim Phoros goes missing in the battle, and is presumed dead. The Lamenters are eventually cleared, but tasked with a one hundred year Pentinent Crusade.
908.M41 Forsythe, the Disgraced One, escapes into the Maelstrom with Lamenters forces still loyal to Lugft Huron.
914.M41 Pentinent Crusade Announced. Lamenters are sent on a 100 years crusade to prove their devoution to the Emperor.
920.M41 Reclusiarch Xeras commissions the creation of his personal Sepulchre Guard near the outset of the Lamenters Crusade.
933.M41 Forces under Master Eurico, Captain of the 1st Company (and acting Chapter Master), clash with Biel-tan Aspect Warriors led by Autarch Skyshrieve on the maiden world Duledain. The Lamenters plunge through the Segmentum Tempestus.
937.M41 Long thought dead, Malakim Phoros is reunited with Lamenters forces after nearly thirty years navigating through the Maelstrom. It is quickly decided that he should retake the mantle of Chapter Master, though no one in the Calix Priesthood was able to determine how he hadn't yet fallen to the Black Rage.
940.M41 Malakim Phoros commissions the Captain of the 10th Company to re-initiate recruitment, despite the edicts of the High Lords of Terra.
945.M41 Strike Force Iltempus reaches the world of Terfirma.
994.M41The Fall of Malvolion leaves the Lamenters Chapter reeling from the strength of the Tyranids. Almost three hundred Battle Brothers are consumed. Chapter Master Malakim Phoros is killed.
995.M41The Lamenters significantly help refugee efforts on the planet Devlan, as it is about to be destroyed by Hive Fleet Kraken.
995.M41- present The Sanguinor appears many times alongside beleaguered Lamenters forces, taking the aspect of The Lamenter.
997.M41 Epistolary Menoloth, now known as the Lost One, returns from the Maelstrom with the daemon blade Walach. After extensive testing it is determined Menoloth remains pure of heart, so he takes command of the newly formed Strike Force Ostro.