Sabamic Gate
The Sabamic Gate (Savamese porte de Sabamie) is a region that marks the boundary between the Sabamic Plain (Dordanie) and Cislacunia (Vallinia); it is the westernmost part of the plains that form the Great Steppe. Most of the area belongs to Ceresora, with the rest in Savam; the region of Outre Garde overlaps both sides of the Gate.
Significance
The Sabamic Gate is so known as it is the main entry point into the Sabamic plain from the steppe. It and the Paltjic Gate in the south were for centuries the two most significant entry points to Messenia from the central continent. It has thus been a major trade-route choke point for at least 4,000 years, and a conduit for invasions. The Secotic Toligonovid-Andarovid alliance, the last major invasion force, recognised its importance in the 1080s by establishing their summer capital at Novigrad, not far away at the northern tip of Lake Velic in the Great Lakes region.
The region of Garde in southern Dordanie got its name, literally "the guard", from its position near the gate and the numerous fortresses that were built there; the Gate proper is surrounded on both side by the region known as Outre Garde, "the further guard". The city of Mardoux, sitting at the boundary between Savam and Ceresora right in the middle of the Gate, has a long history as one of the key fortifications in the region.
Control of Garde and Outre Garde, and especially their transmontane glacis Benovia – the so-called Benovian Question – was a constant cause of conflict between Dordanie and Vallinia, and their successor states Savam and the Ceresoran Empire. The Gate's proximity to Cavino, their capital, has allowed the Vallinians the most consistent control over the region, generally keeping Dordanie out of the northern half of the passages through the gate. Over time their shared boundary stabilised on the river Védomagne, with Vallinia and Ceresora remaining in control of southern Outre Garde, forcing the Savamese to use the river route (or overland routes from the north through passes in the Benovian Range) to access their holdings in Benovia and further east.
Geography
The Sabamic Gate is a major low-terrain gap between the Benovian Range of the Severnistines and the Verbian Uplands, the northernmost extension of the Leucasian mountains. The altitude at the centre of the Gate is 157 metres above sea level.
Counter-intuitively, the Védomagne does not cross from the steppe into the Sabamic Plain through the Gate, but through the nearby Janneur Valley. Geological evidence indicates that the Védomagne flowed through the Gate until at least 500,000 years BP, when it was diverted through the Janneur, a recently opened tectonic graben that was widened by glacial erosion (although on occasions, during subsequent glacial episodes, the Janneur would be blocked by ice and, if the Gate remained open, the river would divert back through the Gate). The Védomagne may have flowed through both the Janneur and the Gate at some point. During the last glacial period the Gate was only briefly obstructed by ice; this formed the bed of the Great Ice Lake that extended from Lake Carles to the Great Lakes.
The Gate proper is an older geological rift, featuring a 68-kilometre-wide stretch of flat terrain (divided into a 52-kilometre main valley and a 16-kilometre secondary passage), including the former course of the river, with no natural obstacles. Elevation is much the same on both sides, creating no visible crest line or mountain pass. There is a drainage divide, although both sides belong to the Védomagne basin.