Simplify the following text for a Grade 12 native English-speaking person.
Original: They also performed land burials which often still included a ship , treasure , weapons , tools , clothing and even slaves and women buried alive with the dead chieftain , for his `` journey to Valhalla , and adventure and pleasure in the after-life . ''
Simplified: They also performed land burials which often still included a ship , treasure , weapons , tools , clothing and even slaves and women buried alive with the dead chieftain , for his journey to Valhalla and adventure in the after-life .