In 1869, Portner was visited by Christian Mathis and Peter Valaer with an invitation to join Peter's brother Jacob as a partner in his brewery and
winter garden in
Philadelphia,
Pennsylvania. He visited Valaer's business, and though he was interested he knew he could not extract himself from his brewery in Alexandria. It was here, though, that he met Jacob and Peter's sister, Anna, whom he fell in love with and married in 1872. Robert and Anna Portner would go on to have 13 children. In 1883, Portner bought Mathis' estate in
Manassas, Virginia, Virginia. When they had visited in the past, Portner's wife had said that the land, with its view of the
Bull Run Mountains, reminded her of her homeland in Switzerland, and that she loved it. As time went on, Portner purchased more and more surrounding farmland, growing his estate to nearly 2,200 acres. Comprising primarily the Weir family's
Liberia estate and
Wilmer McLean's famed
Yorkshire estate, Annaburg would encompass a large portion of the Civil War battlefield, historic mansions, and several earthwork
Fortifications including Fort Beauregard. Portner managed to turn miles of battle-scarred earth and scraggly cornfields into lush pastures for his stock and horse farms, successfully establish a dairy farm at Liberia, and considerably expand Mathis' original orchards and vineyards. He partnered with Washington, D.C. winemaker Christian Xander to produce wine from his grapes, which won a gold medal at the
Paris Exposition of 1900. Annaburg also featured a 300-acre fenced in deer park where Portner often held deer and quail hunting parties. By 1890, the original
Italianate-style house that Mathis had built on the property had become too small for the Portner family, which now included Portner, his wife, and eleven children. He had the house moved and, working with prominent Washington, D.C. architect Gustav Friebus, Portner designed a new home that would combine elements of his favorite European mansions. Built between 1892 and 1894 at a cost of $150,000, Annaburg was a three-story, thirty-five room architectural gem, complete with indoor plumbing, electricity, and porches that wrapped around three sides. It also featured climate control system which combined two of Portner's brewery inventions, making it what is believed to be the first house in the country to have air-conditioning. Annaburg remained in the Portner family until 1947, when his descendants sold the estate to local developer Irving Jackson Breeden. == Later life and death ==