Zygor

The home planet of the Zygons was, by some accounts, Zygor, (PROSE: The Bodysnatchers, HOMEVID:  When Being You Just Isn't Enough) although others indicate it was nameless. (WC: Zygon Stats) It was known to be warmer than Earth and covered in water, which was in the form of lakes with a different mineral composition than those of Earth. It had a slightly higher temperature than Earth as well. There were also no icecaps on the planet. Native lifeforms of Zygor included the unaltered Skarasen and the Zygons. (TV: Terror of the Zygons)

At some point, Zygor was destroyed in a stellar explosion. (PROSE: Doctor Who and the Loch Ness Monster) In the 20th century, Broton said his world was destroyed in a "recent catastrophe", (TV: Terror of the Zygons) although his conception of time was unconnected to the human time-scale. (PROSE: Doctor Who and the Loch Ness Monster) According to one account, the planet was destroyed because of the Zygon war against the Xaranti. (PROSE: The Bodysnatchers) Another account, given by Elizabeth I who had been posing as a Zygon in 1562, said that the Zygons lost their world when it burned in the first days of the Time War. (TV: The Day of the Doctor)

Many Zygons were able to escape Zygor's destruction. They were forced to become nomadic refugees searching for a new planet. (PROSE: The Bodysnatchers)

Four groups of Zygons attempted to make Earth more like Zygor: those who arrived in the 12th century (TV: Terror of the Zygons), those that arrived in the 16th century and plotted to invade in the 21st century (TV: The Day of the Doctor), those that arrived in 1909 (PROSE: Sting of the Zygons), and those that arrived in the late-20th century. (HOMEVID: Zygon: When Being You Just Isn't Enough)

Zygor