The sentinels measured out the ramparts of the fortress with their regular paces.
Advanced English Dictionary
+noun (literary) a soldier whose job is to guard sth Synonym: SENTRY: (figurative) a tall round tower standing sentinel over the river + Large dark pines stood like sentinels guarding the wintry garden.
Random quote: Your vision will become clear only when you look into your heart. Who looks outside, dreams. Who looks inside, awakens.: Carl Jung