John and Nathalie Mayer

A photograph of the married couple John and Nathalie Mayer.

John Mayer was hired by Theodore Havemeyer to manage the Mountainside Farm and its forty workers, while he and his brother Henry were preoccupied with expanding the sugar refinery. John Mayer was evidently very respected by the workers and a huge help to Theodore Havemeyer who did not have the time to run the farm day to day. He married the oldest daughter of Theodore's nine children Lillie Havemeyer. They were married in Villeneuve Switzerland, and it was initially reported that Theodore Havemeyer was opposed. Nonetheless, he relented afterwards and had a new mansion constructed on the property to be a home his daughter Lillie and her new husband. The beautiful brick mansion was built off of Valley Road built and planned by the architect Dudley Newton. It is this mansion that would eventually become known as the Birch Mansion and later the administrative building of Ramapo College. The Mayers would live of the property year round because of John's job as manager. They had four children together and lived an apparently happy life. However, Nathalie died on September 14, 1900 at the young age of 36 from a gunshot wound inside of the mansion. The family did not give much information on the death and said it was an accident, while many others believed it to be a suicide. Nathalie had always seemed to be a very happy person so this caught many people off guard, most of all her husband and their four children. John Mayer and their children would leave Mahwah not long after the funeral and move to Morristown. Frederick Meier was hired as the new manager of the farm, and Theodore's sons would continue to run it, but this was a major loss to the family farm from which it would not fully recover. Theodore's son, also named Henry O. Havemeyer II would largely take over running the farm  from this point until he would sell it to the Birch family.