Lighthouses were first seen in Ultima V, when the lighthouses of Stormcrow, Greyhaven, Waveguide and Fogsbane were erected. However, these structures were not meant to last, and the collapse of the Underworld caused earthquakes that made the lighthouses topple and collapse.
A lighthouse did exist on the Serpent Isle east of Fawn, but at the time of Ultima VII Part Two, the Teleport Storms exchanged it with the Royal Mint of Britannia, while simultaneously relocating the lighthouse to the middle of Britain.
In Ultima IX, new lighthouses had been erected near Britain, Buccaneer's Den, Trinsic and Moonglow. However, in three of the lighthouses, the light crystals were still missing, and the Avatar accepted the job offered by Hans in the lighthouse of Britain to find these, getting them polished and then installing them in the appropriate lighthouse.
Rustic lighthouses were built throughout Britannian waters during the recent years of peace; their bright presence has dramatically lowered the number of ships breaking up on reefs and shoals in dark and storms.