The Cathedral of Love is a building that was erected after the destruction of Empath Abbey, acting as the new center of Love..
After the Great Cataclysm and the destruction of Empath Abbey, the Brotherhood of the Rose built a new center of their activities in Britain, the Cathedral of Love. While smaller and less sophisticated than the old abbey, it nonetheless is one of the biggest buildings of Britain. Specially imposing for the visitor is the great hall with its Ankh-shaped columns, right after the entrance.
Originally, the Cathedral had a much bigger part in the plot of Ultima IX (see Ultima IX Plot Remnants), being used as Amoranth's base in the conflicts raging Britannia. Also it would have been where Shamino would have waited for the Avatar. This is why the building is so huge.