Complex sentence: As Karna lay dying on the battlefield, his father Surya and Arjuna's father Indra fell into a debate as to who among their son's was superior and decided to test Karna's generosity and appeared before him as Brahmins asking for alms.
Split into simpler sentences: As Karna lay dying on the battlefield, his father Surya and Arjuna's father Indra fell into a debate as to who among their son's was superior. Both of them decided to test Karna's generosity and appeared before him as Brahmins asking for alms.