Louis Lebègue Duportail, born in France, was educated at the military
school of Mézières, and considered an excellent engineer. When Congress
instructed our commissioners in Paris to secure a few good engineers,
Duportail was one of the four thus selected; and these were the only
ones engaged by the express authority of Congress. On his arrival in
this country, he was appointed colonel of engineers and promoted to the
rank of brigadier-general on the 17th of November, 1777. He wintered
with the army at Valley Forge, and after the battle of Monmouth, when
the enemy left Philadelphia, he was sent to ascertain what defences
would be necessary to its security, and to plan fortifications for the
Delaware. He also superintended the strengthening of the defences at
Fort Clinton and at Boston. In 1779, he was charged with confidential
despatches to Count d’Estaing, but the subsequent repulse of the French
and American troops at Savannah, and the departure of D’Estaing,
rendered this mission fruitless.
In 1780, being sent to join General Lincoln at Charleston, Duportail
was captured, together with this officer, during the summer; but
through the efforts of Congress, they were both exchanged in the
autumn. In 1781, he carried despatches to the Count de Grasse, and
later the same year had charge of the engineering operations at the
siege of Yorktown, being specially mentioned by Washington in his
despatches after the capitulation. On the 16th of November, 1781,
Congress conferred on him the rank of major-general, and granted
him a six-months furlough to visit his native land. He resigned his
commission in the United States army on the 10th of October, 1783, and
in 1788 was named maréchal-de-camp of the French army. In 1790, he was
made minister of war, but resigned a year later, to accept a military
appointment in Lorraine. Leaving the army in 1792, he returned to this
country in 1794, and remained here until 1802, when, being recalled to
France, he died at sea during the voyage home.