Complex sentence: In 1791, under Sheridan's management, the building was demolished to make way for a larger theatre which opened in 1794; but that survived only 15 years, burning down in 1809.
Split into simpler sentences: In 1791, under Sheridan's management, the building was demolished to make way for a larger theatre which opened in 1794. However that survived only 15 years, burning down in 1809.