Robert L. Mattheisen

Robert L. Mattheisen

May 18, 1939-September 30, 2026

Robert was born May 18, 1939, in Danvers, Minnesota, where he grew up on a farm as the youngest of seven children. From an early age, he possessed an extraordinary curiosity and love of learning. As a boy, he set a goal for himself to read every book in the Danvers library, a goal he eventually accomplished. That lifelong love of books, ideas, history, music and learning remained with him throughout his life. Robert served in the United States Army and later built a career as a technical writer. His work eventually took him to Honeywell, where he contributed to defense-related projects and wrote technical manuals associated with aircraft systems used in the F-14 and F-15 fighter aircraft. He later worked for Unisys, where he concluded his career as a technical writer. He spoke often and fondly of the people he worked with at Unisys and valued the friendships and camaraderie he found there.

Outside of work, Robert was an avid reader and a devoted lover of classical music. He remained intellectually curious throughout his life, always interested in learning something new, asking another question or discovering another book. But the center of Robert’s life was his family. He met the love of his life, Sandra “Sandee” Larson, and together they built a family through the adoption of their three children, Matthew, Kara and Maria. Robert was a devoted husband and a deeply loving father and grandfather. He gave generously of his time, energy and resources to provide for his family, often placing their needs ahead of his own. His love for Sandee endured long after her death at the age of 58. For years afterward, before going to sleep at night, Robert would take out her photograph, speak to her and wish her good night. It was a simple ritual that reflected a love that death never entirely interrupted.

Robert is preceded in death by his parents, Louis and Vera; his beloved wife, Sandee; and his seven siblings. He is survived by his children, Matthew (Mary) Mattheisen, Kara Mattheisen and Maria (Christian) Yates; grandchildren, Shane (Odyssey) Mattheisen, Emma (Storm) Lenz, Meghan (Brock) Baumgartner, William Mattheisen and Gabriella Mattheisen; great-grandchildren, Avelina, Malachi, Kidus, Vander and Nyden; sister-in-law, Jackie (Terry) Hoel; and many nieces, nephews, extended family members and friends.

A memorial service will be held at 11:00 a.m. Wednesday, October 14, 2026, at Elim Lutheran Church, 20971 Olinda Trail North, Scandia, Minnesota. The family will greet friends one hour prior to the service at the church.

Private interment will take place at Fort Snelling National Cemetery.