Although Lillo was neither a professional man of the theatre nor at home in literary circles, he was not the naïve artist he is sometimes described as having been. He wrote mostly in verse, but sometimes in prose. Lillo was a playwright who had some wild successes (most notably The London Merchant, which successfully popularized domestic drama), as well as some flops. He enjoyed some royal patronage for some of his works, performing The London Merchant before Queen Caroline and inscribing some of his plays to members of the royal family. Lillo also enjoyed a close personal and professional friendship with bookseller John Gray. Lillo's will indicates that he was prosperous, able to make bequests of money and personal property to a number of relatives as well as houses and holdings of land in and out of the City.