Thomas's trips as special envoy to some of the great courts of Europe further encouraged his interest in art collecting. He became noted as a patron and collector of works of art, described by Walpole as "the father of virtu in England", and was a member of the Whitehall group of connoisseurs associated with Charles I. He commissioned portraits of himself or his family by contemporary masters such as Daniel Mytens, Peter Paul Rubens, Jan Lievens, and Anthony van Dyck. He acquired other paintings by Hans Holbein, Adam Elsheimer, Mytens, Rubens, and Honthorst