What is 5. To set up in business; to place advantageously in a fixed condition; -- used reflexively; as, he established himself in a place; the enemy established themselves in the citadel called?

establish — 5. To set up in business; to place advantageously in a fixed condition; -- used reflexively; as, he established himself in a place; the enemy established themselves in the citadel. (Webster's 1913.)