Simplify the following text for a Grade 9 native English-speaking person.
Original: Hindenburg , old and senile as well as bedridden from being very sick , thought he was meeting Kaiser Wilhelm II , and he called Hitler `` Your Majesty '' when Hitler first walked into the room .
Simplified: Hindenburg , old and senile , thought he was meeting Kaiser Wilhelm II , and called Hitler `` Your Majesty '' .