Emma Boehmer was born at St. Helena, Nebraska, July 4, 1876. Both of her parents came from Westphalia, Germany. Emma entered the convent at Clyde as a postulant on August 28, 1900 and was invested with the Benedictine habit on January 23, 1901. She made profession on the same date the following year, receiving the name of Sister M. Petronilla. Perpetual vows were made on September 27, 1907.

Sister was of a very cheerful disposition, with a hearty laugh and a fine sense of humor. It is said she enjoyed nothing more than playing a good trick on someone, and enjoyed it too when the tables were reversed.

Sister served as prefectress of the Academy for a time, and also as sacristan. She was portress for many years, beginning in the old Academy building, when accommodations were poor. She served all visitors cheerfully and devotedly, often at the cost of self-sacrifice. She was much loved by all for the warmth of her hospitality and her kind and thoughtful charity.

Sister M. Petronilla died of cancer on October 4, 1935, after a comparatively short but very painful illness, which she bore patiently and cheerfully. She was fifty-nine years old.