(References to Fianna)
Note: X and Y are coordinates (light years on XY plane) relative to Terra at (0, 0)
X: -141.34 Y: 20.78 [e]
Fianna is a primarily agricultural world. Its largest continent is named Lysidas.
In 3017, the planet was contested between the Lyran Commonwealth and the Free Worlds League, with a standoff in place. A battalion of the Oberon Guards commanded by Redjack Ryan was hired to garrison Lysidas. Faced with civil protesters, the mostly inexperienced MechWarriors eventually opened fire on the protesters. This led to a vicious circle of escalation, with reprisals causing more unrest and leading to more acts of sabotage and terrorism against the garrison force. Ryan's forces burned entire cities and damaged a large fusion reactor but eventually had to retreat into an old Star League bunker that held chemical weapons. They threatened to use those weapons against the planet if the government would not provide them with a JumpShip to leave the system. The government gave in, but as they were about to leave the planet with the last Leopard DropShip the last elements of Ryan's unit were overrun by an angry mob and the chemical weapons were set free. This, possibly exacerbated by the damaged reactor, poisoned the atmosphere of half the planet and killed millions.
- 2271 - Inhabited world 
- 2340 - Federation of Skye 
- 2341 - Lyran Commonwealth 
- 2596 - Lyran Commonwealth 
- 2750 - Lyran Commonwealth 
- 2765 - Lyran Commonwealth 
- 3017 - contested between Lyran Commonwealth and Free Worlds League
- 3025 - Lyran Commonwealth 
- 3030 - Lyran Commonwealth 
- 3040 - Federated Commonwealth 
- 3052 - Federated Commonwealth 
- 3057 - Lyran Alliance 
- 3062 - Lyran Alliance 
- 3130 - Lyran Commonwealth 
- 3135 - Lyran Commonwealth 
- 3145 - Wolf Empire 
- Trial of Faith
- Handbook: House Marik, p. 13, "Marik Commowwealth world within the Free Worlds League before  and after at their founding in "
- Handbook: House Steiner, p. 13, "Federation of Skye world within the Lyran Commonwealth befor  and after at their founding in "
- Historical: Reunification War, p. 158, "Inner Sphere Map "
- Handbook: Major Periphery States, p. 25, "Rim Worlds Republic At the Fall of the Star League "
- Era Report: 2750, p. 36, "Inner Sphere - 2750"
- Historical: Liberation of Terra Volume 1, p. 10, "Inner Sphere - 2765"
- Historical: War of 3039, p. 132, "Inner Sphere - 3040"
- Map of the Inner Sphere 3130
- Era Report: 3145, p. 10, "Inner Sphere - 3135"
- Era Report: 3145, p. 39, "Inner Sphere - 3145"