The mystery men behind the purchase of the famed Astor estate at 778 Park Avenue has been revealed—it's Daniel and Brett Sundheim. One of those names strikes a bell: Daniel Sundheim is a portfolio manager at Viking Global Advisors, a New York hedge fund with over $12 billion in assets under management. [via Bloomberg]

It was reported last month that the penthouse on the 15th and 16th floor of the building was purchased for $21 million, but no names were attached to the purchase. Earlier this year, Swiss money manager Daniel Forcart tried to buy the apartment for $20 million, but his offer was rejected by the co-op board.

The residence has been on the market since 2008, when it originally listed for a whopping $46 million. Many said the price had been hyper-inflated because of the Astor name -- the residence used to belong to the late Brooke Astor, a famed socialite and philanthropist nicknamed "NYC's fairy godmother."

It's a pretty swanky pad—with a classical decor and french doors throughout. There's 5 bedrooms, 6 terraces and 5 fireplaces; and it's got the personal touches that a city's fairy godmother would put on her home.