The Metronists Society and the Calcularium League

The Metronists Society and the Calcularium League are guilds of engineers, artillerists, architects and cartographers. While the two guilds share the same professions in membership, they are bitter rivals and have been, at times, outright enemies. 

The Metronists Society teaches that the world must be meticulously modeled, then measured and built to scale. They have a heavy reliance on geometry and the principle of similarity. The Calcularium League teaches the use of secret formulas and algorithms to calculate measurements from drawings. 

On their surface these two guilds would seem to have much in common, but every builder knows that to invite both to a job site is to invite actual bloodshed. While the work is all but indistinguishable by the common man, members each insist that their work is pure and the others amounts to either idolatry (on the part of the Metronists) or sophistry (on the part of the Calcularium).

Their great rivalry came to head and became outright enmity under the rule of Favian III, High King of Westrun. While Favian's predecessor had commissioned the Northern Wall, it came to completion under his rule. Working from the same set of plans, the Metronists began at the Sea and worked inland. The Calcularium began at the mountains and build toward the sea. As the two teams of laborers drew close, it became apparent that the walls would not meet without visibly altering one of both of their courses.

Both guilds found this solution to be the responsibility of the other, and each refused to alter course. The wall came within ten feet of each other before the bloodshed began. Relatively few (perhaps two dozen) were involved in the conflict, but hardened soldiers who were witness to it claimed it was the most appalling and unspeakably brutal melee they had ever seen. 

To correct the error, Favian ordered the Seam built on that spot. The Seam is an irregular tower, offset from both walls and from which both courses of the wall can be observed to run straight for many miles.

The enmity between the two guilds remains to this day. There are tales of sabotage and hired assassins that are told in both guild houses. There is some truth to these tales.