Complex sentence: The opening night was on 12 October 1805 with a performance of Richard III, with an unknown actor in the lead, and was not a success however the theatre soon established a good reputation and thriving business under the management of William Wyatt Dimond.
Split into simpler sentences: The opening night was on 12 October 1805 was a proudction of Richard III, with an unknown actor in the lead. Though not a success, the theatre soon established a good reputation and thrived under the management of William Wyatt Dimond.