Mr. Robert Theisen, of Apple Valley, Minnesota, passed away in the morning hours of Monday, April 19, 2021 at NC Little Hospice in Edina, Minnesota. He was 78 years old. Bob was born in Port Washington, Wisconsin on March 17, 1943, son of Elmer Theisen and Doris Meyer Theisen. Bob grew up in the Belgium, Wisconsin area, and graduated from Port Washington High School with the class of 1961. After high school, he attended college at the University of Wisconsin – Whitewater where he graduated with a bachelor's degree in Chemistry. On August 14, 1965, he married Agnes M. Kish at St. Teresa Catholic Church in Springfield, Ohio. Mr. Theisen worked as a sales representative for Texaco, Ethyl Corporation, Phillips 66, Chevron, and CHS until his retirement in 2014. Bob enjoyed fishing in northern Minnesota and Canada with his close friends and family, as well as researching, organizing, and documenting a comprehensive genealogy of the Theisen family. Bob is survived by his wife Agnes of Apple Valley, two children Christopher (Mira) of Arvada, Colorado and Sean (Alexandra) Theisen of Ann Arbor, Michigan; loving grandfather of Annalise, Steven, Kaira, Andrew, and Ian. He is further survived by two sisters Kay (John) Kleckner of Fredonia, Wisconsin and Sue (Dan) Last of Washington Township, Michigan, and a host of beloved nieces, nephews, other relatives, and many friends. He is preceded in death by his parents. A Mass of Christian Burial will be celebrated on May 15, 2021, at 12:30 PM at Divine Savior Parish, Holy Cross Chapel, 5330 County Highway B, Belgium. Father Gideon Buya will preside over the Mass. He will be laid to rest at St. Mary Parish Cemetery in Lake Church, Wisconsin. Visitation will take place on Saturday, May 15th AT THE CHURCH from 10:30 AM until the time of Mass. Masks and proper social distancing will be required. In lieu of flowers, memorials are suggested to the NC Little Hospice (www.littlehospice.org). The Eernisse Funeral Home, Belgium, is honored to serve the family. Online condolences may be left at www.eernissefuneralhome.com