Charles Ellicott Commentary 1 Kings 11:27

"And this was the reason why he lifted up his hand against the king: Solomon built Millo, and repaired the breach of the city of David his father." — 1 Kings 11:27 (ASV)

Solomon built Millo. —See 1 Kings 9:15; 1 Kings 9:24. This was apparently after he had built the Temple and the palace, some twenty years after his accession, when the delight in magnificence of building apparently grew upon him, and with it the burdens of the people.