Complex sentence: In 1808, Daendels decided to quit the by-then dilapidated and unhealthy Old Town--a new town center was subsequently built further to the south, near the estate of Weltevreden.
Split into simpler sentences: In 1808, Daendels decided to quit the by-then dilapidated and unhealthy Old Town. A new town center was subsequently built further to the south, near the estate of Weltevreden.