Eglon king of Moab עגלון מלך מואב

Eglon gathered to himself the children of Ammon and Amalek, struck Israel and took the City of Palms, that is Jericho. For eighteen years tribute was brought to him.

Then the book tells the story in unusual detail: Ehud son of Gera, a left-handed man of the tribe of Benjamin, makes a sword a cubit long and straps it on his right side—where no one looks. He brings the present, dismisses the bearers, comes back and says, "I have a secret word for you, O king." The king is left alone in the upper chamber; Ehud says, "I have a word of God for you"—and the king rises from his seat.

Of Eglon himself the text says exactly one thing besides his name: he was a very fat man. That is not a judgment but a detail on which what follows depends: the haft went in after the blade.

The window is the eighteen years of verse 3:14. By Seder Olam Rabbah 12 they fall within Ehud's eighty, so the count begins at the start of his term.