One of the first worlds settled in the Eire Subsector and still of significant importance, Derry in recent centuries has become overwhelmed by tension between the system’s different human populations. Intractable disputes over political allegiances, ethnolinguistic communities, and attitudes towards human biological diversity and evolution may yet produce catastrophe.
The first inhabitants of the Derry system were travellers from Earth, distant descendants of the crew of the ESA generation starship Niall Noigiallach. Funded by the European Union member-state of Ireland, the Niall Noigiallach was–like the other generation starships of its class–modelled on the three vehicles of the European Space Agency Long-range Colony Mission launched in the mid-21st century. Carrying two thousand passengers and ten thousand embryos, the Niall Noigiallach was launched in 2089 with the goal of establishing an Irish colony world hundreds of parsecs to rimward of Sol, in a cluster on the fringes of the Local Arm.
Unlike many other Terran generation starships of that era, the Niall Noigiallach survived to reach its destination, in 4688 CE decelerating into orbit of the most clement garden world in the Dublin binary system (0706 Eire). The mainworld of Baile Átha Cliath and its ancillary worlds were colonized successfully, implementing the long-dead social planners’ design to create a distinctly Irish interstellar-capable society. Completely isolated from their home system and its interstellar civilization, by the 49th century CE the Dublin system supported a thriving civilization capable of mounting secondary colonization and expeditionary missions of its own.
Among the first launched was to the Feabhal system four parsecs away, where an unusual double planet had been detected during deceleration by the Niall Noigiallach, orbiting in the life zone of a young BY Draconis star. On arrival, the Bréanainn V expedition determined that the scans by the founding generation starship were accurate. Six planetary bodies orbited the K5 star Feabhal, four rocky planets and two gas giants. Two rocky planets shared the second orbit, 0.49 AU from the primary, one a high-gravity waterworld with an ammonia-water ocean, the other a desert world larger than Mars in the Sol system with some glaciated seas, both orbiting a common centre of gravity in a bit under two months. Although the system was only fifty million years old and the Feabhal system’s worlds were geologically unstable, both worlds in the life zone–Doire and An Ghealach, in Galanglic “Derry” and “The Moon” did support basic microbial life, while the planets and smaller world of the system were rich in mineral resources. In the end, the Dublin government chose to concentrate its colonization efforts on more Earth-like worlds such as An Baile Meánach (Ballymena), Béal Feirste (Belfast), Corcaigh (Cork), and Gaillimh (Galway), where fully-fledged daughter civilizations could be settled, but the worlds of the Ferbhal system did receive more than their fair share of research settlements, whether floating on the oceans of Doire or anchored on the sea floor, or on the dryer surface of its moon.
Dublin and its interstellar community were brought roughly into distant contact with Sol and its interstellar community in 5346-49 CE, when the prosperous but technologically backwards subsector was conquered by Solomani migrant fleets fleeing instability in the Banners and Ahriman Sectors and attracted to a promising human civilization free from the instability of home. Equipped with jump drive and otherwise vastly more advanced than the worlds of the “Eire” subsector–Baile Átha Cliath itself was only tech level A and most other worlds substantally behind, while the Solomani were at tech level C–the migrants were easily able to overwhelm the peaceful subsector. The proclamation of the Empire of the New Marches in 5351 established a fully-united interstellar state for the first time in the sector’s history.
The coreward worlds of the subsector were soon overwhelmed by Solomani migrants, the world of Béal Feirste becoming the Solomani’s new homeworld in the subsector, while a Solomani military elite established itself elsewhere. In the more than three millennia since the departure of the Niall Noigiallach, the people of the Eire subsector had come to diverge strongly from the Solomani norm, knowledge of the English ancestral to the Galanglic spoken by the Solomani literally becoming academic to people who spoke only one dialect or another of Irish, with the natives knowing nothing and caring even less of what had happened to their ultimate homeworld and its people since their departure. The biology of the humans of the Eire subsector, too, had come to diverge sharply from the Solomani norm, the genetic engineering that had adapted the settlers of Dublin to life on a low-gravity world with a thin atmosphere and an unusual number of allergens creating a variant human race. Various of the secondary colonization missions brought Dublin colonists to new worlds with unique conditions meriting further engineering. In all, the Empire of the New Marches identified three broad classifications of subsector natives which would each count as separate variant human races. As elsewhere, the biologically and culturally distinctive subjects of an aggressive empire were treated badly, often exploited as labour on many of the secondary systems (like Derry’s) opened up by the Empire’s superior technological base
By the end of the 55th century, internal squabbles in the Empire’s governing classes along with a native resurgence on Dublin and the worlds to rimward led to the Empire’s collapse. Solomani retreated to the coreward quarter of the Eire Subsector, where they founded a Solomani-supremacist Empire of Man centered on the world now known to its Solomani majority as Belfast. After some disorder, in 5599 CE the freed worlds united in their Republic, the Poblacht, governed once again from Dublin but now possessing a technological base capable of standing up to their nearest neighbours. Tensions between the Empire of Man and the Poblacht persisted, as irredentists in the Poblacht lay claim to the worlds in the Empire of Man taken by the Solomani, particularly worlds which retained native majorities of population like Doire. Full-fledged war is distant, as neither polity feels strong enough to invade the other, but cross-border terrorism is becoming distressingly common.