LIGONIER -- After Gen. John Forbes arrived at this fort near Loyalhanna Creek in November 1758, he decided to spend the winter here. But intelligence gathered on the day of a friendly fire incident prompted him to change his strategy.

In the twilight of Nov. 12, 26-year-old Col. George Washington rode outside the fort with a detachment of 500 Virginia soldiers; Lt. Col. George Mercer led 500 men, too, by a different route. The two leaders planned to surround a force of 140 French and Native American warriors who, they believed, were trying to steal the British Army's cattle and horses. Three enemies were captured; the rest withdrew to Fort Duquesne, which was 50 miles to the west.

Later, the two Virginia units encountered each other in the darkness, and, mistaking each other for the enemy, engaged in friendly fire that killed 38 soldiers and two officers.

"Before Washington could stop it, 40 men were killed or missing. If this happened today, it would be quite the scandal," said Martin West, director of Fort Ligonier.

If you go: Fort Ligonier

• Where: Fort Ligonier Museum is at 200 S. Market St., Ligonier. Admission fees are adults $8; children 6 through 14, $4.75; 5 and under free.

• Hours: It's open daily May 1-Oct. 31. Hours are Mon.-Sat., 10 a.m. to 4:30 p.m.; Sunday, noon to 4:30 p.m.

• Information: 724-238-9701 or fortligonier.org. The Tour of Pennsylvania, a bicycle race that begins in Philadelphia and ends in Pittsburgh, stops in Ligonier Saturday.

Following Forbes' footsteps

"Pennsylvania's Forbes Trail," a new travel guide and history from Taylor Trade Publishing, focuses on gateway communities across the state through which Gen. John Forbes passed on his 1758 expedition to capture what is now Pittsburgh's Point.

Staff writers Len Barcousky and Marylynne Pitz revisited those communities for a travel series:

• Lancaster
• Carlisle
• Fort Loudoun
• Bedford
• Ligonier
• Pittsburgh

Among the three prisoners was a British deserter who told his interrogators that Fort Duquesne was weak because the Indians had abandoned it and the French lacked provisions.

Seizing this opportunity, Forbes picked a force of 2,500 men, gave them a few pieces of artillery and, with Washington in the lead, ordered them to march toward Fort Duquesne. While in Turtle Creek on Nov. 24, those soldiers heard an explosion. Cavalry sent out to reconnoiter returned with the news that smoke hung over Fort Duquesne.

The next day, a seriously ill Forbes was carried on his litter into the charred ruins of Fort Duquesne, which he renamed Fort Pitt in honor of William Pitt the Elder, Britain's secretary of state. Four months later, Forbes died in Philadelphia, probably from stomach cancer.

In 1759, the British enjoyed what they called "the year of victories" with battles won at sea and on land and, at the Treaty of Paris in 1763, took control of North America.

Today at the Fort Ligonier Museum visitors can see a new exhibition about the most significant and decisive conflict of the 18th century, which Winston Churchill called the first world war.

Conceived and researched by the museum's staff, the long-term installation is called "The World Ablaze," a phrase coined by Voltaire, the French philosopher who commented on what Europeans called the Seven Years' War.

As 300 new objects were acquired between 2001 and this year, "The World Ablaze" is a substantial addition to Fort Ligonier's collection.

"I'm so happy our subject wasn't the 100 Years War," Mr. West joked, adding that artifacts were collected from England, Scotland, France, Spain, Portugal, the Netherlands, Italy, Austria, Germany, Sweden, the Philippines, Canada and the United States.

The museum's other exhibits also have been upgraded. In the building's foyer hang the colorful flags of four British regiments that served in the French and Indian War. To your left is a gallery with a detailed map of Fort Ligonier, beautifully restored dioramas and items found in archaeological digs at the fort, including cuff links, liquor bottles, tools and shoes.

Another room, decorated in the style of the Queen's Gallery at Buckingham Palace, showcases 13 original oil portraits of significant figures from the war. Red walls set off the gilded frames. Here are King George III in his coronation robes, a young George Washington painted by Rembrandt Peale and Sir John Ligonier astride his horse. Sir John Ligonier served as field marshal for the British Army and that's why Gen. Forbes named the post at Loyalhanna for him. He never visited the fort but was known for his military prowess.

A few steps from the museum is the reconstructed Fort Ligonier, which boasts a breathtaking range of cannons, howitzers, gun carriages and Conestoga Wagons. The fort also contains a blacksmith's shop, a hospital and two large clay brick ovens, which were used to bake brown bread for the troops. Soldiers subsisted on dried beef and bread, so rum and whiskey were popular.

Brad Mooney, proprietor of Heritage Restorations, was hired in 1996 to reconstruct Fort Ligonier's outer retrenchment, hospital, officers' quarters and the fascine cannon battery as well as artillery, carts and wagons.

The fort faced west and guarded a gap in the Chestnut Ridge. Its walls are made of stacked logs; the pointed poles on top, called fraising, were designed to repel enemies who tried to scale those walls.

Inside the fascine cannon battery is a 2-ton, 8-inch howitzer, which fired exploding shells.

"The Indians had never experienced shell fire," Mr. Mooney said, and it frightened them so much that they retreated from their attack on Fort Ligonier, broke their alliance with the French and finally left the field of battle.