LONDON (REUTERS).- The family of Princess Diana will auction a painting by Flemish master Peter Paul Rubens as part of a clearout sale valued at $30 million designed to ensure the financial future of the Althorp estate. Earl Spencer, Diana’s brother, is head of the estate, and plans to marry for a third time later this year, according to newspaper reports. Diana, who was married to heir-to-the-throne Prince Charles, was killed in a car crash in Paris in 1997. The highlights of a collection including paintings, furniture, porcelain and horse-drawn carriages are works by Rubens and 17th century Italian master Il Guercino. The Rubens, “A Commander being armed for Battle,” was painted in 1613 or 1614 and is expected to fetch 8-12 million pounds ($12-18 million). The bearded man gazing toward the viewer has been named by some experts as Emperor Charles V. The painting has been at the late princess’s family home Althorp for more than 200 years, and was originally described as the “