Garstang was the palace on the Isle of Thanedd. The walls of the palace emit a strong aura and block magic interference, thanks to Nina Fioravanti. The process of imposing these magical barriers took her nearly a year to perfect. This barrier, and a strict no-weapons policy, made it an ideal location for the Conclave of Mages.
Near the summit, where you can see those gleaming domes, is Garstang palace. The great Conclave of Mages will begin there in a few days. And there, look, on the very top. That solitary tower with battlements is Tor Lara, the Tower of Gulls..."
— pg(s). 66, Time of Contempt (UK edition)