Simplify the following text for a Grade 6 native English-speaking person.
Original: All that is known with certainty is that he spent time as a child at both places , and he stipulated in his will that his body be interred at Jerez de los Caballeros , where other members of his family were also interred .
Simplified: All that is known with certainty is that he spent time as a child at both places . In his will , he wanted to be buried at Jerez de los Caballeros , where other members of his family were also buried .