Simplify the following text for a Grade 9 native English-speaking person.
Original: The Latin name of Arbon , Arbor Felix ( meaning happy tree ) , first appears in around 280 and is mentioned in the Itinerarium Antonini in 300 .
Simplified: The Latin name of Arbon , Arbor Felix ( meaning happy tree ) , first appears in the Itinerarium Antonini in 300 .