USS Constitution
The USS Constitution sits in Dry Dock 1 at the Charlestown Navy Yard in Boston during a media tour of the ship on Jul. 17, 2017 Getty Images

World’s oldest commissioned naval vessel still afloat, USS Constitution, made a comeback Sunday after a 26-month-long restoration project. The ship that turns 220 in October was undocked from the Charlestown Navy Yard Historical Park in Boston. It later entered the Boston Harbor.

Launched in 1797, the wooden ship is one of the six original frigates authorized for construction by the Naval Act of 1794. It was designed by Joshua Humphreys, an influential and successful ship builder, and it was constructed at Hartt's Shipyard in Boston, Massachusetts. The name "Constitution" was chosen by former President George Washington.

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The ship’s extreme size caused difficulty during the launch in 1797. It took three separate tries on three different days to get it off the ramps and into the water. The first duties of the ship with the newly formed U.S. Navy were to provide protection for American merchant shipping during the Quasi-War with France and to defeat the Barbary pirates in the First Barbary War.

The USS Constitution fought and won three major engagements during the War of 1812 against the United Kingdom. It is best remembered for the capture of rival HMS Guerriere. In the course of the 35-minute battle with Guerriere, witnesses observed British 18-lb. iron cannonballs were bouncing harmlessly off the Constitution’s 25-inch oak hull, leading a sailor to cry out, “Huzza! Her sides are made of iron!” earning her the famous nickname “Old Ironsides," according to Navy's magazine All Hands. During this war, Constitution's range of guns typically consisted of thirty 24-pounder (11 kg) cannons, with 15 cannons on each side of the gun deck.

In 1855, the Constitution retired from active military service, but it continued to serve the country, first as a training ship and later as a touring national landmark, according to History.com. Since 1934, it has been based at the Charlestown Navy Yard in Boston.

Over the years, Ironsides has enjoyed a number of restorations, including the most recent one that began in 2015. The recent round of restorations extends the life of the nearly two-feet (61-centimeter) thick vessel. A report by Bloomberg said the recent work also included replacing 100 hull planks and installing 2,200 new copper sheets, 500 of which were signed by nearly 100,000 museum visitors.

The report also quoted Robert Gerosa, the Constitution's commanding officer, saying: "The ship has been the cornerstone of the Navy for a long time. To be a part of the ship is truly an honor."

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The event held Sunday in the Charlestown Navy Yard, marking the comeback, indicated the end of this round of restoration. The vessel would remain docked at a nearby pier until September to undergo more restoration, and it would then reopen for public tours.

The website of the Naval History and Heritage Command states the Constitution’s mission is to "encourage understanding of the Navy's role in war and peace through educational outreach, historical demonstration, and active participation in public events." As a fully commissioned Navy ship, visited by nearly half a million people every year, its crew of 60 officers and sailors participate in ceremonies, educational programs, and special events while providing free tours to visitors all year-round.