Terra

"Terra is the core of the Republic. Take Terra, and the rest shall fall."

Emperor Arkus, Emperor of the Imperium

"Earth"
Terra was the birthplace of humanity. Originally named Earth by it's inhabitants, the world has always been regarded as the most important planet in the galaxy.

Red Sun Republic
The Red Sun Republic was founded here in 2278 by Terra's various governments.

Ghost Fleet Crisis
Ghost Fleet Crisis

Emperor Arkus conquered Terra two years after his emergence. The planet was not bombarded, but it was subjugated by imperial forces.