Simplify the following text for a Grade 11 native English-speaking person.
Original: Jien records that Itoku was the second or third son of Emperor Annei , but the surviving documents provide no basis for speculating why the elder brother or brothers were passed over .
Simplified: The GukanshÅ records that Itoku was the second or third son of Emperor Annei , but the surviving documents provide no basis for making guesses about why the elder brother or brothers were passed over .