The Esquiline hill is on the eastern side of the city opposite the Capitoline hill. It included the Cispius, Fagutal and Oppius hills and overlooks the valley in which the Colosseum was later built by Emperor Vespasian.
From a tourist’s point of view, this is one of the areas with least attractions although its main attraction, the very ancient basilica of Santa Maria Maggiore, is an absolute must. Other minor churches in the area are worth a visit too for their antiquity. San Pietro in Vincoli contains Michelangelo’s famous sculpture of Moses (you might have to pay a ticket to see it though).
There are indications that this hill began to be populated in the later part of the Roman Kingdom under the 6th king Servius Tullius, who constructed some of the earliest and most durable walls around the city (Servian Walls).
Even in ancient times much of this hill was one of the more populated and poorer areas of the city known as the Suburra (a sort of Soho in London I suppose). Emperor Claudius‘ wife Messalina remains in popular imagination as one of the most renowned Roman women, albeit for the wrong reasons! was said to sneak out of the palace on the Palatine hill to come and enjoy her work as a prostitute here. The southeastern part of the hill, in itself a hill called “Oppius” was the more residential and upper-class area and the remains of Trajan’s baths and Nero’s Golden House (the Domus Aurea) are still to be seen. PS: Nero’s Domus Aurea may now be shut off to visitors, which is a real shame.
A note of particular interest is that many of the very ancient churches which are found on the Esquiline hill stand on the remains of ancient Roman houses. This is because until Christianity was legalised in ancient Rome the followers of Jesus, St. Peter and St. Paul would meet in secret in each other’s homes. Churches were later built over the more important meeting places.