Espero was a human colony in the 61st century. To the Ecumenical Council, this was a second Garden of Eden, another shot at paradise, in the return of the ways of the Holy Apostolic Church.
They left behind millennia of human history, bringing only sacred writings and some technical manuals, but ultimately Espero turned to hell, as the resources promised by HomeWorld were inaccessible, the climate was hotter than anticipated, insects were everywhere and clean water was hard to find. They had nothing to trade, and almost died out within fifty years of arrival.
As expressed by the prince Javill, “Espero is the poor cousin. We have been abandoned by the other colonies, left to our own devices. Every month brings news of the advance of other worlds – new technologies, new beliefs, new alliances formed. The Catholic heritage on which we were founded has become a liability.” “The whole of Esperon culture, the origins of the colony, were based on making a new start – building a new future out here among the stars, not repeating the mistakes of the past.” (Halflife)
Countries on Espero included Anjon, which was ruled by a democratically elected Prime Administrator. There were eight nation states on Espero, all of which had proper democracies save for Saiarossa, which had a royal family. Others included Eden, Paradiso Grande, another Eden, Pelucidar, and Marselle. (Halflife)
Espero had indigenous insects. Other animals native to Espero included burrowbears, which occasionally killed and ate humans; mokeys, small monkey-like mammals often kept as pets; and tree-rats and creatures called elephines which dwelt on the southern plains. (Halflife)
The Eighth Doctor once saved all the life on Espero from an energy wave created by a Maker called Reo. (Halflife)
The Doctor later sent K9 to Espero in search of Madame Xing. (The Gallifrey Chronicles)