In time immemorial, Arthach was an elven summer palace. Later, during an experiment to control the flow of water in the Sansretour Marsh carried out by then-duke of Toussaint, Adam of Nazair, Arthach was flooded and severely damaged, and thus a permanent swamp was created around it.
In or shortly prior to 1275, the ruins were overrun by a group of bandits being led by Antoine Straggen. The bandits raided and robbed people and settlements throughout northern Toussaint, while the palace ruins served as their base of operations. On one of the still-standing stone platforms in the ruins, the hanse installed a large bonfire that would serve as a signal for reinforcements if the ruins were ever attacked.
- The experimental attempts to manage the waters of the Sansretour Marsh carried out by Duke Adam of Nazair did not prove very successful – to put it lightly. They flooded a great number of villages, private estates and even Arthach, an elven summer palace. These experiments were what gave the Sansretour Marsh its current shape and put half of Crane Isle permanently underwater. They also created an unpleasant bog to the north of the city where none can tread in true safety.