Simplify the following text for a Grade 10 native English-speaking person.
Original: In Brussels he saw `` the things which have been sent to the king from the golden land '' â '' the Aztec treasure that HernÃ n CortÃ s had sent home to Holy Roman Emperor Charles V following the fall of Mexico .
Simplified: There he saw `` the things which have been sent to the king from the golden land '' â '' the Aztec treasure that HernÃ n CortÃ s had sent home to Holy Roman Emperor Charles V following the fall of Mexico .