892-IV was the fourth planet of the 892 system. As Spock noted, it was a M-class planet with a striking resemblance to Earth. The land/water proportion, density (5.5g), diameter at the equator (7917 ml) and atmosphere (78% nitrogen, 21% oxygen) were exactly like those on Earth. However the layout of the continents was different. (TOS: "Bread and Circuses")
History
This planet was cited as evidence of Hodgkin's Law of Parallel Planetary Development. The English language had evolved, and a parallel of the Roman Empire existed here.
By the 23rd century, the planet had reached the development of Earth's 20th century. Technology included radio communications, road system and powered transportation (such as the Jupiter 8), but no atomic power. Gladiator games became televised. With each century even slaves received rights to medicine and government payments in their old age; the Empire eventually managed stopping rebellions and even wars for 400 years achieving stability.
The Romans believed in a pantheon of gods, but a nascent movement known as Children of the Son, a parallel to Christianity on Earth, started to be embraced by gladiators, slaves and even Senators, disrupting the stability of the conservative Empire.
In 2262, the Federation class 4 stardrive survey vessel SS Beagle was badly damaged by a meteor in the system and a landing party beamed down to obtain iridium ore for repairs. The part were met by the locals, led by Proconsul Claudius Marcus who considered ruinous, to his highly conservative society if word of its existence should be carried elsewhere; the officers were regarded as captured barbarians and forced to fight as gladiators.
Captain James T. Kirk and the crew of the USS Enterprise visited the planet 892-IV six years later, on stardate 4040.7 after investigating the debris of the Beagle. (TOS: "Bread and Circuses")
Geography
892-IV had several oceans and at least three continents. It was politically subdivided into a number of provinces.