The Valnaxi-Wurm War was a centuries-long war between the Valnaxi and the Wurm. The struggled lasted centuries and ended in the 2nd century.
History
The Wurm planned to take over the home planet of the peaceful Valnaxi planet which, due to its position, would allow them to conquer the rest of the galaxy. The resulting war grew to span across the seventeen systems of the Wurm Empire.
By 118 A.D. there was no chance of winning for the Valnaxi. They hid all of their treasures, including the Lona Venus, The Flight of the Valwing, and The Shriek, across the galaxy to be hidden in warrens on various planets, including Earth on Africa, all guarded by Golems as part of their long trap for the Wurms. For the next 2,000 years, with the Valnaxi extinct, the Wurm searched for all warrens, with the aid of Jaxamillian Faltato, to crush every last representation of the Valnaxi.
Seven chosen Valnaxi landed in a spaceship on Earth that was buried after the thousands of years. In 2118, the Wurm found what they thought was the greatest warren, on Earth, and invaded Africa to crush it. By that time the Valnaxi Council had lost their bodies and their intelligence was contained in smoke. They had set up a trap with a fake deactivation plaque for the Wurms to find, thinking they were deactivating the Golems. Having encountered Golems at every warren and therefore condintioned to fight them, the Valnaxi had now fooled them and as soon as a Wurm touched the plaque, its physical and pyschic abilities would be copied and produced so that the entire Valnaxi race could be reborn and then travel back to their Wurm-infested home world, thereby allowing them access to the spirit of their planet.
This trap was ruined, however, when Solomon Nabarr touched the plaque and they were given the Human form to copy, seeking out Rose Tyler so that they could have a female version, finding the two sexes necessary but viewing the human reproduction process as clumsy and inefficient. A Male and Female were created as templates but the Valnaxi planned to turn all Humans into Valnaxi so that they could fight the Wurms.
Through the Doctor's intervention, King Ottak was killed and the Valnaxi ship was sent out into space by a volcanic eruption so that the fighting would leave Earth. The Male and Female stayed behind.(NSA: The Art of Destruction)