The sale of Dupont Circle’s Patterson Mansion may not have been the quickest deal in Washington real estate—the historic home has been sitting on the market since the spring of 2013—but on Monday the property finally closed at $20 million. In February, the developer submitted plans to convert the mansion into 90 350-square-foot luxury micro-units, combining the original marble and brick four-story building with a new, seven-story addition. The property boasts a storied history—originally built in 1901 for Chicago Tribune editor Robert Patterson and his family, in 1927 the mansion was briefly the temporary home to President Calvin Coolidge while the White House underwent renovations.