Simplify the following text for a Grade 5 native English-speaking person.
Original: Saint-Denis was founded by Ã tienne RÃ gnault in 1669 and became the capital of RÃ union island in 1738 .
Simplified: Saint-Denis was founded by Ã tienne RÃ gnault in 1669 . The city became the capital of RÃ union island in 1738 .