Lusitania is a world first introduced in Speaker for the Dead. Catholic by religion, Portuguese by language and culture, the planet was colonized by Brazilian settlers from Earth, which would later convert the alien species living there to Christianity. It is named after the Roman name, in Latin, for Portugal. This planet is inhabited by all three Ramen races - the Pequeninos, the Formics and Humans. It contains a deadly virus called the descolada that would destroy the ecosystem of any other planet if it were to spread.
The planet's only human colony was restricted in growth so as not to interfere with the Pequeninos; likewise, contact between humans and Pequeninos was forbidden except for the local researchers. The policy proved unworkable, as the Pequeninos had, early on, discovered how to circumvent the security fence of the colony and had been able to observe humans using technology, including witnessing agricultural practices and the arrival of a space-faring shuttle. The planet was also chosen by the Formic queen as a good place for re-emergence because of high levels of mineral deposits, permission from the Pequeninos to settle and a lack of human settlement, including blind spots where satellites did not look.
Read more about this topic: List Of Ender's Game Series Planets