The Aos Sí (Aos Sí)

The Tuatha Dé after they lost Ireland: not gone, just moved underground, and not to be named aloud.

When the Milesians took Ireland, the Tuatha Dé Danann did not leave. The agreement, as the tales have it, divided the country in two: the Milesians got the half above ground and the Tuatha Dé got the half below it. They went into the sídhe, the mounds, and they are still there.

Aos sí means the people of the mounds. So does daoine sídhe. What you will mostly hear in Irish country speech is neither, because naming them directly was unwise. They are na daoine maithe, the good people, or na daoine uaisle, the gentry, or simply themselves. The politeness is a precaution, not an affection.

They are not small and they are not sweet. In the older material they are tall, beautiful, proud and extremely dangerous to offend. They take milk, they take butter, they take children and leave changelings. They hold their own courts and fight their own battles, and a person who interrupts either is in serious trouble.

The practical consequence is on the landscape and is still visible. A ringfort or a lone hawthorn is understood to be theirs, and in a great many Irish fields you can see where a plough has gone carefully around one rather than through it. That is why the country still has tens of thousands of earthworks standing in the middle of good farmland.