Even though Mr. and Mrs. Marland had to move from the Mansion in the early 1930's, they retained ownership while he served in Congress and as governor of Oklahoma. They opened the mansion for parties and special events and E.W. used it as his campaign headquarters whenever he ran for office. Six months before he died, Mr. Marland sold the complex to an order of monks, the Discalced Carmelite Fathers. He kept the chauffeur's cottage and the surrounding land and left them to Lydie in his will.
The Carmelite Fathers established a college of philosophy at the mansion in 1941 and were cloistered there until 1948. They then sold the complex to the Sisters of St. Felix for $50,000.
The Felician Sisters renamed the estate Assumption Villa, and operated a nunnery and high school at the mansion. The nuns themselves lived in the mansion, on the upper level. They built the chapel and the administration building. They also built Angela Hall as a private high school, and in the 1960’s, they added a dormitory. All but Angela Hall have been removed.
In 1975, the Felician Sisters announced that they were planning to sell the mansion and surrounding property and move to New Mexico. Conoco offered to pay half of the purchase price if the City of Ponca City would pay the other half. A one-cent sales tax was proposed by the city to fund their part.
Lydie Marland returned to Ponca City during this time and wrote a letter to the citizens, asking them to support the sales tax and save the mansion. The sales tax issue did pass, and the City of Ponca City became the owner of the Marland Estate, including the mansion and all the other buildings on the 30 acre complex. The total purchase price was $1.4 million.