There's barely mention of the city in the histories, and none still live who remember it. But it was a beautiful city once, and prosperous. And now it is gone. Forgotten.
Sil'dih (古代都市シラディハ, Kodai Toshi Shiradiha?) was a city-state that existed long ago beside Ul'dah in Final Fantasy XIV. It existed in Thanalan as a sister City-state to Ul'dah, both having been born from Belah'dia, but vanished from sight until the Calamity exposed the sealed ruins. Like Ul'dah, it was ruled by Lalafell.
History and LocationsEdit
Sil'dih was ruled by the King of Springs, King Lalawefu. His financial reforms brought the city-state prosperity, but a combination of tax increases and untimely droughts led to civil unrest. The flood control developed by this nation soon drew the attention of the parched Ul'dahn citizenry, and a de facto war broke out.
The two nations were equally matched, and Sil'dih knew that its prosperity would be short-lived if drastic measures were not taken. To improve their odds they attempted to zombify their fallen soldiers, but over time lost control of their arcane creations. Ul'dah used this to justify an official declaration of war, and in their triumphant crusade sealed the gates of Sil'dih, wiping them out with their own perverse plague.
Ruins of Sil'dih can be visited in Central and Western Thanalan, recently uncovered during the Calamity. Before the rediscovery of these ruins the civilization was nearly forgotten. However, thanks to the daughter of the Miner's Guildmaster, Nenekku, and other Eorzean researchers such as Erik in the Monk quest line, much of the above history is now optionally available.
A remnant of the Sil'dih Aqueducts (likely relevant to the aforementioned flood control) was hidden in the furthest tunnels of the Copperbell Mines, which was not instanced in 1.0. It was later blocked by a strange wall of webbing, and only available via temporary Aetherial Gates during the first of the Lambs of Dalamud events. After this particular event ended the Sil'dih Aqueducts remained sealed, never to be accessed again.
The grandness and elegance of the aqueducts (which are still inaccessible) suggested Sil'dih rivaled, or even surpassed, Ul'dah in architectural aptitude. That they were more-or-less forgotten until recently suggests Ul'dah wanted to forget them and tried to erase them from history, or that they either lacked the means or motivation to keep adequate records.