(April 5, 1716 - May 17, 1774) was a Swiss-born American painter, primarily of portraits. He was active mainly around Charleston, South Carolina, in which city he remained almost without competition for the bulk of his career.
Theus was born in the city of Chur, in the Swiss canton of Graubenden, and was the eldest child of Simeon and Anna Walser Thees. He was nineteen when he immigrated with his family to the Province of South Carolina, whose General Assembly had provided land grants and transport funds to encourage European Protestants to settle in the colony. Simeon Thes was given 250 acres (1.0 km2) of land along the Edisto River in what was then Orangeburgh Township,