That scar –
as the old nurse cradled his leg and her hands passed down
she felt it, knew it, suddenly let his foot fall –
down it dropped in the basin – the bronze clanged,
tipping over, spilling water across the floor.
Joy and torment gripped her heart at once,
tears rushed to her eyes – voice choked in her throat
she reached for Odysseus’ chin and whispered quickly,
"Yes, yes! you are Odysseus – oh dear boy
I couldn’t know you before…
not till I touched the body of my king!"

– Homer

The Odyssey, Book 19, lines 528-538. Odysseus’ old nurse Eurycleia sees through his disguise just as she is washing his feet. The instant she spots his scar she recognizes him and is overcome with tears of joy. Even after an absence of twenty years, Eurycleia is still caring and loyal to her king.