Original: ... Celeste Aida \/O/ "Heavenly Aida"). Aida, who is also secretly in love with Radames, is the captured daughter of the Ethiopian King Amonasro, but her Egyptian captors are unaware of her true identity.
Simplified: One of them is the Ethiopian king, Amonasro, father of Aida, although the Egyptians do not know who he is.