According to the Monk, the Halcyon were "one of the most highly civilised races in the cosmos". The species came from the planet Halcyon.
Biology[]
The Halcyon were different enough in appearance from humans and Time Lords for the Monk to place an SEP filter around him and Tamsin to not make them stand out. (AUDIO: The Resurrection of Mars)
Culture[]
The nearest thing the Halcyon had to a religion was their giving of thanks to nature. The Halcyon knew about war — in the words of the Monk, they weren't "ignorant" — but they had no need for it. The Monk said they had created "transcendent works of art". (AUDIO: The Resurrection of Mars)
History[]
By the 33rd century, the Halcyon had wiped out all forms of disease on their planet. 20 billion Halcyon lived on Halcyon, but had "everything they could ever need". Around this time, the Ice Warriors attacked, destroying all life on the planet, and making it their new home. The Eighth Doctor told the Monk the destruction of Halcyon was "a part of the Web of Time". (AUDIO: The Resurrection of Mars)
Behind the scenes[]
In The Resurrection of Mars, actor Graeme Garden refers to the species as the "Halcyon", while Niky Wardley says "Halcyons".