|Part of Dark Age|
|Republic of the Sphere
|Commanders and leaders|
|Chancellor Daoshen Liao
Coordinator Yori Kurita
Gunji-no-Kanrei Matsuhari Toranaga
|Capellan Confederation Armed Forces
Draconis Combine Mustered Soldiery
|Republic Armed Forces
Armed Forces of the Federated Suns
In January 3149 the Republic of the Sphere dropped the Wall and returned to the interstellar stage with a series of lightning moves intended to buttress the Republic's defenses against its enemies. Subsequently Operation ERUPTIO saw the Republic Armed Forces ravage the Dieron Military District's units and kill its Warlord on Dieron itself. Meanwhile the Capellan Confederation mounted its own assault against the now-exposed Republic worlds on its rimward border, gaining several worlds with surprising ease. 
The success of the CCAF offensive led Capellan Chancellor Daoshen Liao to believe Terra itself was vulnerable, but he was also wary of potential Republic traps. To counter any Republican machinations, he dispatched an embassy to Luthien to propose an alliance between his realm and the Draconis Combine. While initially reluctant to risk Terra falling to a rival House as a result of their assistance, the revelation that Devlin Stone had returned to lead the Republic swayed the Combine's leadership into agreeing to the Capellan proposal. The resulting Unity Pact, signed on 21 April, included an agreement to a joint offensive against the Republic and its Federated Suns ally. 
Operation TIAMAT, Phase One
The DCMS struck first in June with attacks upon four Federated Suns worlds in the Terran Corridor, swiftly seizing all of its targets. These conquests cut the Suns off from its Republic ally and created the first shared border between the Combine and Confederation since the mid-Third Succession War.
The DCMS' victories enabled the Capellans to focus their efforts against the Republic itself, launching their attack in August against Epsilon Indi, Bryant and Liberty. While the CCAF faced sustained resistance only on the last world, the swiftness with which they all fell fueled Daoshen Liao's concern that the Republic was enticing his soldiers into an ambush.
Operation TIAMAT, Phase Two
Kanrei Toranaga initially planned to mount his military's portion of Wave Two in late October, but AFFS strikes against the Dragon's Tongue in September forced a change of focus to the Combine's other major front. While the renewed threat from Task Force Perceval was contained by mid-November, the Combine was unable to simultaneously attack the Republic as planned.
In light of the oddly swift downfall of its previous targets, the CCAF attacked its first Wave Two targets in October with a sense of caution. The Capellans' fears proved unfounded, with Procyon and New Home both falling in short order. Nonetheless, Daoshen limited the next assault to a single target, Keid, deciding that this victory would give his military direct access to Terra while minimizing the risk of Republic surprises. Keid also fell swiftly, leaving the Confederation on the doorstep of humanity's homeworld.
Capellan Halt and the Combine's Second Wave
As 3150 dawned the Capellan military assembled its forces in the region rimwards of Terra and Daoshen Liao moved to his ancestral homeworld, all in anticipation of invading Terra. However the regiments earmarked for that invasion's first wave all suffered a spree of sabotage in March which both weakened them and led to Daoshen postponing the invasion until he could ascertain the Republic's defenses on Terra.
The Draconis Combine finally mounted its second wave in February 3150, invading three Republic worlds across the Combine's border. The Republic's sabotage attacks against the Capellans left the Dieron District's new Warlord Mineo Tadashige to dispatch scouting raids first. Upon learning that the target worlds of Asta, Altair and Fomalhaut were lightly defended by militia, the DCMS attacked and seized all three systems.
The damaging covert strikes against the CCAF in March led to Daoshen ending the Confederation's portion of TIAMAT. Coordinator Yori Kurita decided likewise shortly after due to the Combine's worsening situation on the Federated Suns front. Nonetheless, Operation TIAMAT had resulted in territorial gains for both of the Unity Pact members, placing both within striking distance of Terra itself. 
- Shattered Fortress, p. 64-65
- Shattered Fortress, p. 66
- Shattered Fortress, p. 67-68
- Shattered Fortress, p. 72-73
- Shattered Fortress, p. 73-75
- Shattered Fortress, p. 79-80
- Shattered Fortress, p. 80
- Shattered Fortress, p. 101, "Timeline"