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.
[3]Theus took on a variety of commissions during his early career, including painting and guilding the steeple of St. Michael's Episcopal Church in 1756, a job for which the congregation's commissioners paid him 77 pounds and 10 shillings for his labor and supplies.
[1] Theus was able to build a highly successful practice for himself in the three decades he spent in Charleston; this was due largely to the fact that for much of that time he was the only painter in town with any significant reputation.
At the estate sale, one Edward Oats purchased ""a great many PORTRAITS of Men, Women, and Children" with the intent of finding interested buyers for the set; whether or not he was able to sell the paintings off is unknown.
The will reveals how successful Theus was in his chosen profession; besides holding nearly 3,000 pounds in cash, he owned a house in Charleston, 200 acres (0.81 km2) of land in Orangeburg County, a town lot in Orangeburgh, and seven slaves.
The wedding likely took place around September, because in that month the artist purchased a brick house at the corner of Mazyck (today Logan) and Broad Streets in Charleston.
[1] Theus typically confined himself to uncomplicated compositions, and the bulk of his portraits are bust-length works, approximately thirty by twenty-five inches at their largest; like many portraitists of the era, he also produced miniatures.
In some, he chose to use a landscape background, rather than the plain backdrop reserved for his adult subjects; others are allotted a variety of props, including a fishing line and hook, an acorn and a pet squirrel, or a piece of fruit.
Costume remains the dominant focus of most of his portraits; he took greater care in depicting the colorful details and trimming of clothing than in showing his sitters' faces.
His advertisement in the Gazette indicates that he was willing to paint landscapes and decorative work, including coats of arms and family crests, in addition to human subjects.