On April 29, 1948, Representative Howard Worth Smith (D-VA) introduced a bill proposing "the coinage of 50-cent pieces in commemoration of the two-hundredth anniversary of the founding of the city of Alexandria, Virginia." The city was founded in 1749.
Its history began, however, 80 years before. In 1669, Robert Howsing was granted 6,000 acres of land along the Potomac River by Sir William Berkeley, the Governor of the Colony of Virginia, in exchange for bringing 120 colonists to the area; the grant was authorized by King Charles II. The northern border of the tract was Little Falls; its southern boundary was Hunting Creek.
History shows that Howsing never developed the land he was given; he sold it to John Alexander within a month for 6,000 pounds of tobacco. The tract of land was in a rich tobacco growing region and the crop would ultimately factor prominently in the city's founding. A tobacco warehouse was built near Hunting Creek around 1730 to support trade and general commerce; a community began to develop in the surrounding region.
In late 1748, the Virginia General Assembly received a petition to create a town at Hunting Creek Warehouse on the Potomac River (it was spelled "Potowmack" at the time). George Washington helped survey the area and is generally credited with drafting a simple map or layout for the proposed town.
Virginia Governor William Gooch, on May 11, 1749, signed the Act that established the town of Alexandria on 60 acres of land theretofore owned by Philip Alexander, John Alexander and Hugh West. The town name would be drawn from the surname of the Alexander family which had owned the bulk of the property. It would grow and prosper and go on to become an important colonial trade center.
As the city's 200th anniversary approached, the Alexandria Bicentennial Commission was created to plan and coordinate its birthday celebrations. Among the events it organized were a parade, an historical pageant and a gala ball.
The Commission also looked to mark the occasion with appropriate souvenirs, chief among them was a commemorative coin. It sought 50,000 coins that it could sell at a premium to help defray costs of its planned celebrations. Unfortunately for the Commission, its coin bill did not garner significant support in the House and never emerged out of committee.
In May 1948, Smith introduced a bill calling for a commemorative stamp. The Post Office was against the idea, as it believed that its commemorative stamps should be used for events of national vs. local significance. (Sound familiar?) Smith and the Commission eventually prevailed over the Post Office's objections and had a six-cent airmail stamp issued.
The stamp featured the City Seal of Alexandria at its center, flanked on the left by Gadsby's Tavern, an important early meeting place for the city that was built in 1770, and on the right by the city's first mansion - the Carlyle House - which was built in 1752-53 by John Carlye, a prominent British merchant. The house became a central gathering place for early Alexandria's social and political movers and shakers.
The Commission sponsored two special first day covers featuring its stamp. One depicted the same two buildings shown on the stamp, while the other reproduced the 1846 Alexandria Postmaster's Provisional stamp. (The Provisional stamp was a local issue that pre-dated the country's national postage stamps; the Alexandria Provisional stamps are extremely rare with only seven surviving examples known.)
Since I can't show a commemorative half dollar for Alexandria, I've included examples of each of the Bicentennial Commission's official covers for its stamp.