In "The Children's Hour," Longfellow uses military metaphors to describe the sudden invasion of his study by his three daughters. After plotting to take him by surprise, they enter his castle wall, climbing into his turret "O'er the arms and back" of his chair. And if the speaker tries to escape, he's instantly surrounded. "They seem to be everywhere."

Of course, Longfellow is exaggerating for comic effect. As invasions go, this one's actually rather cute. Having broached his inner sanctum, the three little girls proceed to shower their father with kisses and throw their arms around him. They may be banditti, but crucially, they are "blue-eyed banditti," which reveals that they are ultimately sweet and innocent, despite their boisterous behavior.

The sudden natures of the girls' invasion of their father's study prompt the speaker to use military metaphors. Their manners are somewhat abrupt, to say the least, conjuring up as they do images of historical invasions in the learned speaker's mind.

All the same, he's eventually able to repel this sudden attack upon his castle by keeping his daughters in the fortress of his heart, from which he will never let them go. He will put them down into the dungeon, but his is the nicest dungeon one could possibly imagine, occupying as it does the round-tower of his loving heart.