Complex sentence: According to historical record, the Shwedagon Pagoda has existed since 588 BCE, making it the most ancient historical pagoda in Burma and in the world.
Split into simpler sentences: According to historical record, the Shwedagon Pagoda is over 2500 years old since BC 588. Shwedagon is the oldest Pagoda and the most ancient historical Pagoda in Burma and in the world.