Third Succession War
The Third Succession War ran from 2866 to approximately 3025. Compared to the previous Succession Wars, the Third was marked with almost constant, but low-intensity, warfare as the Successor States fought over increasingly dwindling resources and technology. The tail-end of the Third Succession War was the initial starting point of the BattleTech game.
After three decades of high-intensity warfare, the Second Succession War spluttered to a conclusion as fighting tapered off in 2863. As with the similar conclusion of the First Succession War, with the conflict ending due to both military and economic exhaustion of all parties rather than any decisive victory, tensions between the Successor States remained high. Despite this, many hoped peace would prevail as the Inner Sphere went nearly two years without conflict, with Lyran Commonwealth's Estates-General and Free Worlds League Parliament both pressing for stand-down of their respective militaries, a refocusing on civilian reconstruction and end to war-time austerity measures. 
In response to efforts by these parties, Archon Elizabeth Steiner attempted to broker a formal peace treaty with Captain-General Philippa Marik in 2864, the success of these prompting the Captain-General to request these efforts be expanded to include the other Successor States. Representatives from all five houses met on New Earth in November 2864, but it soon became clear just how divided the Inner Sphere remained - the Draconis Combine representative indicated he was nothing more than a observer and that any treaty the others agreed on would be approved or rejected by Luthien at a future date, the Capellan Confederation refused to sign any treaty that did not make provision for the return of all the territories it had lost in last two wars - which the Free Worlds League and Federated Suns vociferously opposed - with the FedSuns representative Luther Davion making equally unrealistic claims for the other houses to accept him for position of First Lord. Aside from the Combine representative being arrested and executed by the Lyrans as a spy, the talks collapsed after seven fruitless weeks with nothing being achieved.  
A group of Capellan and Free Worlds businessmen under the banner of the "Peace of Money Movement" likewise attempted push for a permanent peace treaty, but aside from First Prince Michael Davion, none of the other Successor Lords would give them the time of day, with a number of the other Houses convinced that First Prince Michael's enthusiastic and lavish support meant the movement was actually a Davion plot and the movement's claims of the Lyrans profiteering from the previous conflict alienating the Commonwealth.  
While many in the Inner Sphere hoped peace had finally come even if the formal attempts at peace treaties had failed, the bitter animosities between the Successor States meant conflict could just as easily resume, needing only to be triggered by those who wanted the war resumed, such as the quasi-religious communications company ComStar. Focused on the supposed "Word of Blake", ComStar guarded and preserved the Star League's technological secrets in the belief that when the Inner Sphere collapsed after the Great Houses had destroyed themselves, ComStar would rise to power as the saviour of humanity. Seeing the prophecy foretold by the Blessed Blake endangered when Precentor ROM provided evidence that Inner Sphere would likely recover the bulk of Star League LosTech within three decades, in 2866 Primus Raymond Karpov and the First Circuit authorized ROM to filter information about the so-called Shadow War in the Draconis Combine between elements of the Internal Security Force loyal to Coordinator Miyogi Kurita and his sister Roweena to agents of Lyran Commonwealth and Federated Suns. Just as Karpov had hoped, in typical Kurita fashion when Miyogi learned that outsiders knew of the Combine's internal troubles and with Lyran traders making embarrassing inroads in the Rasalhague Military District, the simmering tensions along the Combine-Commonwealth border exploded into open warfare again on the Commonwealth's coreward border that soon swept across the entire Inner Sphere, signaling the beginning of the Third Succession War.  
The intensity of this conflict never approached that of either the First or Second Succession Wars. This lessening was more likely due to reduced military capacity rather than a change of tactics. The scavenger necessities that had begun to emerge during the Second Succession War carried over and each Great House rapidly realized that they needed to preserve their precious technical resources.  
Two main components of this era were the evolution of a set of informal rules of engagement, similar to old Terran chivalric values, and a neo-feudal system. The rules of engagement were similar to the Ares Conventions whereby 'Mech forces fought over industrial facilities, but were restricted in their attacks on those facilities and civilians. Major battles, especially between mercenary units, were fought in stages with both sides allowing enemy Techs to enter the battlefield during periods of truce to attend to damaged 'Mechs. Especially important was a tradition of paying a ransom for safe passage after surrendering to a superior force. Also, JumpShips became strictly off-limits as a military target as it was quickly recognized that without JumpShips, nothing would be possible and interstellar civilization itself would collapse.    
The feudal system evolved throughout the years because, just as during Terra' original Dark Ages, the capacity for central governance of the Inner Sphere's stellar nations had evaporated. As a result, each Successor Lord controlled their house via a hierarchy of nobles who, in exchange for full authority over their worlds, pledged their fealty and their 'Mechs to the service of their liege lord.  
Notable events of the Third Succession War
Operation Killing Stroke
- See the Operation Killing Stroke page for more detailed information.
In 2949 newly invested Captain-General Thaddeus Marik started planning for a bold three-pronged invasion of the Lyran Commonwealth, with the main objective being the capture of Solaris and the former Terran Hegemony worlds of Denebola and Wyatt. Unfortunately upon presenting the plan to Parliament in 2950, the body firmly rejected the abrasive Thaddeus's demand for over 30 regiments of troops and extensive funding, underlining this by authorising all worlds within two jumps of the Lyran and Capellan borders to invoke the Home Defense Act, removing over two-thirds of the troops the Captain-General had requested.   
Refusing to be dissuaded from his grand venture, Thaddeus initiated low-level coups against minor states to install leaders more favourable to supporting him, as well as using his personal funds to hire ten mercenary units. Eventually launching a truncated version of his plan, Operation Killing Stroke would ultimately prove to be amongst the most costly and least successful offensives mounted by the Free Worlds League Military, netting only one world - Cavanaugh II - after three long and brutal years of campaigning.   
The Great Lee Turkey Shoot
- See the Great Lee Turkey Shoot page for more detailed information.
Choosing to combat the increasing weakness of the Capellan ground forces in the late 30th Century with overwhelming air support, after a House Marik raid near Ingersoll in 2952 was repulsed without a single Liao loss, Chancellor Ingrid Liao decided to launch a major offensive against the Davion-held world of Lee. Site of a AFFS regional supply center as well as a critical maintenance facility for AeroSpace Fighters and increasingly rare Land-Air 'Mechs, Ingrid committed six fighter regiments (over 200 AeroSpace Fighters) and a sizable ground force to the mission.     
The MIIO however learned of the plan well in advance, giving First Prince Peter Davion plenty of time to reinforce and direct the planet's defense himself. Thanks to their advanced warning the Davion defenders met the Capellan forces in space, immediately assuming aerospace superiority. The Battle of Lee, later more commonly called the Great Lee Turkey Shoot, saw the sleeker and faster Davion AeroSpace Fighters easily cripple over forty of the slower and older Capellan Thunderbird and Eagles, the Liao 'Mechs, tanks and infantry lacking sufficient air-cover and taking heavy losses before being pushed off-world.      
The Deep Raid of 2987
- See the Deep Raid of 2987 page for more detailed information.
Shortly after becoming Archon, Alessandro Steiner reviewed intelligence reports with his Strategies and Tactics division and came to the realization that a lull in the fighting between Houses Marik and Liao presented a unique opportunity. With both sides having pulled back to regroup and recoup their losses after years of heavy fighting, Alessandro correctly guessed the Marik troops on the border would be relaxed and vulnerable to an attack from an unexpected quarter, including those guarding a "secret" BattleMech factory under construction on the League world of Ling.     
Sending the elite 6th Lyran Guards and the 54th Fighter Support Wing aboard a JumpShip disguised as a commercial freighter, after two months of tense jumps, the Steiner forces reached the Ling system unchallenged, destroying the BattleMech factory with only minimal losses to themselves. While the League forces extracted a measure of revenge by inflicting heavy losses when the Lyran forces made ill-considered strikes against Park Place, Ryerson, Irian, Nathan and Bordon as they made their way back to Commonwealth space, the loss of the vital BattleMech factory was a bitter blow.   
Conclusion of the Third Succession War
The Third Succession War drew to a close ironically not through any military victory but with another call for lasting peace. Recognizing humanity's slow but steady slide away from the glories of the Star League-era and toward barbarism, Archon Katrina Steiner of the Lyran Commonwealth issued a Peace Proposal to the other House leaders in 3020. Hanse Davion, First Prince of the Federated Suns, was the only Successor Lord who welcomed the initiative. The result of their talks was the Federated Commonwealth Alliance Document, which Prince Hanse Davion and Archon Katrina Steiner signed on Terra in 3022. In addition to trade and military agreements, the F-C Document contained a secret provision betrothing the Archon's daughter in marriage to Hanse Davion. Though the marriage would not occur until the twelve-year-old Melissa came of age, this was the first step on the road to eventual unification of the Lyran Commonwealth and the Federated Suns.
The other three Successor Lords were aghast at this sudden shift of power, which would lead to the eventual creation of a single state nearly as large as their three Houses combined. In October 3022, the Draconis Combine, the Free Worlds League, and the Capellan Confederation hastily signed the Concord of Kapteyn. Though not as far-reaching in scope as the F-C Document, it called for an end to active hostilities between the three states, who now pledge mutual defense against combined Federated Commonwealth as well as agreements to coordinate their overt and covert efforts to derail the Davion-Steiner alliance.
Perhaps most active in the covert attempts was the Capellan Confederation under the leadership of Chancellor Maximilian Liao. Liao agents had already subverted Hanse Davion's brother-in-law Michael Hasek-Davion, who was now providing them with valuable military intelligence. When the Chancellor next initiated Operation Doppelganger, a scheme to kidnap and kill Hanse Davion in order to replace him with a doppelgänger his scientists had created, he went too far. Davion eventually escaped capture and imprisonment and returned to his place on the throne, vowing revenge and setting the scene for the Fourth Succession War.
- House Steiner (The Lyran Commonwealth), pp. 66-67 "History - The Third Succession War - Lull - Once more into the Breach"
- House Marik (The Free Worlds League), p 38 "History - The Second Succession War - Last Chance for Peace"
- Handbook: House Marik, p. 37 "History of the Free Worlds League - Second Succession War"
- House Davion (The Federated Suns), p. 77 "History - Third Succession War - Man of Peace"
- House Kurita (The Draconis Combine), p. 74 "History - The Third Succession War"
- ComStar, p. 32 "History of ComStar - War Renewed - The Karpov Legacy"
- House Kurita (The Draconis Combine), p. 76 "History - The Third Succession War - Is War the Natural State of Man?"
- Handbook: House Kurita, p. 54 "History of the Nation - The Third Succession War"
- MechWarrior: The BattleTech Role Playing Game, p. 8 "A History of Human Space - The Succession Wars (2785-Present)"
- MechWarrior: The BattleTech Role Playing Game, Second Edition, pp. 111-112 "Historical Overview - The Succession Wars (2785-3030)"
- Handbook: House Liao, pp. 32-33 "History of the Nation - Third Succession War - Elastic Defense"
- Handbook: House Davion, p. 61 "History of the Federated Suns - Third Succession War - Rise of the Brotherhoods - Armistice - Back to Battle"
- House Marik: The Free Worlds League, p. 42
- Handbook: House Marik, p.41
- Field Manual: Free Worlds League, p. 8 "A House Divided - Poltics of Command - Resolution 288"
- House Liao (The Capellan Confederation), p. 50 "History - The Succession Wars - Shift to Aerospace"
- House Davion (The Federated Suns), pp. 87-88 "History - Third Succession War - Knights of the Void"
- Handbook: House Davion, p. 67 "History of the Federated Suns - Third Succession War - Rise of Brotherhoods - The Purge"
- Handbook: House Liao, p. 34 "History of the Nation - Third Succession War - The Great Lee Turkey Shoot"
- Technical Readout: 3025, p. 134 "AeroSpace Fighters - SPR-H5 Sparrowhawk"
- Technical Readout: 3025 Revised, p. 152 "AeroSpace Fighters - SPR-H5 Sparrowhawk"
- House Steiner (The Lyran Commonwealth), p. 77 "Alessandro Steiner"
- House Marik (The Free Worlds League), pp. 46-47 "Concession to Parliament"
- Handbook: House Steiner, p. 51 "Strategic Errors"
- Technical Readout: 3025, p. 162
- ComStar (sourcebook)
- Field Manual: Free Worlds League
- Handbook: House Davion
- Handbook: House Kurita
- Handbook: House Liao
- Handbook: House Marik
- Handbook: House Steiner
- House Davion (The Federated Suns)
- House Kurita (The Draconis Combine)
- House Liao (The Capellan Confederation)
- House Marik (The Free Worlds League)
- House Steiner (The Lyran Commonwealth)
- Technical Readout: 3025
- Technical Readout: 3025 Revised