In 1863, federal law provided for seizure of property for nonpayment of taxes. And under it, Arlington, the peacetime home of Robert and Mary Anna Custis Lee, became a national cemetery. Down the hill in Alexandria, a smaller but even more Lee-laden house, Lee-Fendall, was also seized and became an annex to the Grosvenor House military hospital. Built in 1785 by Philip Richard Fendall, the house was festooned with Lees from the start: Fendall married three Lee women. In all, 37 members of the family lived there. In 1937, John L. Lewis, president of the United Mine Workers of America, bought the house, where he lived until his death, in 1969. The home was eventually purchased by the Virginia Trust for Historic Preservation and is now maintained as a museum. Today it will celebrate the births of two of the most prominent Lees, Revolutionary War Gen. Henry “Light Horse Harry” and his son, Confederate Gen. Robert E. The event runs from 2 to 4 p.m. at the Lee-Fendall House Museum, 614 Oronoco St., Alexandria. $4. (703) 548-1789. (Janet Hopf)