Principality of Gibson
Originally part of the Principality of Regulus, Gibson and a number of neighboring worlds was among that province's members that chose to break away as a result of Captain-General Gerald Marik's campaign against the Regulan-based Scourge of Death. Citing the landmark Camlann vs. Free Worlds decision, the new province was established in 2699 and its MPs accepted in Parliament a year later. Six worlds made up the Principality's membership from or before 2750 until at least 2864: Gibson, Clipperton, Molokai, Aconcagua, Mohács and Ibarra.   
For over two centuries after its founding the Principality was a staunch supporter of House Marik and firmly opposed to Regulus, both in Parliament and militarily during the Succession Crisis of 2882. This outlook swiftly changed in 2919 with the revelation that Captain-General Samuel Marik had heavily infiltrated Gibson's government with SAFE agents to secure control of that world's BattleMech industry. As a result, during the Marik Civil War the province refused to support either side during the whole conflict, and as of 3025 the somewhat paranoid provincial government generally sided with the Parliamentary opposition, though it was also careful to maintain its independence from Regulus as well. At some point prior to this, Aconcagua, Mohacs and Ibarra had become independent worlds, leaving the Principality as a three-world province.  
In 3053 Word of Blake exiles from ComStar were permitted to establish themselves on Gibson. A Regulan-backed anti-Blakist insurrection led to a brief-but-brutal conflict which was ended by Paul Masters and the Knights of the Inner Sphere. The Blakists remained entrenched on Gibson throughout the next two decades and through their Jihad, until a Regulan task force rendered Gibson lifeless in 3078. Following this the effectively moribund province was absorbed into the newly-established Regulan Fiefs.  
- House Marik (The Free Worlds League), p. 64, "Principality of Gibson"
- Handbook: House Marik, p. 31, "Timeline: Serpent in Eden"
- Era Report: 2750, p. 36, "Inner Sphere - 2750" Map
- Handbook: House Marik, p. 38, "Free Worlds League after Second Succession War" Map
- Historical: Brush Wars, p. 21-22, "Provincial Loyalties"
- Handbook: House Marik, p. 42, "Free Worlds League after Third Succession War" Map
- Handbook: House Marik, p. 55, "Timeline: Kerensky's Return"
- Dark Age: Touring the Stars (3130), p. 70
- Dark Age: Touring the Stars (3130), p. 72