Complex sentence: In April 1817 Thompson advertised his presence in Providence, Rhode Island, where he intended to paint portraits "in the Hall of Blake's Hotel"; portraits he painted during this time have not yet been identified.
Split into simpler sentences: In April 1817 Thompson advertised his presence in Providence, Rhode Island, where he intended to paint portraits "in the Hall of Blake's Hotel". Prtraits he painted during this time have not yet been identified.