"We decided back in 2000 to start concentrating on those years at the fort," Robertson says. "This way, we can focus more on the historic period of the fort's use, to make it more interpretive and educational for people."
Settlers began inhabiting the area in the 1730s. The fort was built in 1756 - during the French and Indian War - when the area was on the far western frontier of the British colonies in North America.
In 1791, the state of Maryland decided Fort Frederick no longer served a military purpose and the facility was sold at public auction. For more than a century, the property was farmed by private owners. In 1922, the fort was repurchased and refurbished, eventually becoming Maryland's state park.
An 18th-century market fair gave area residents a chance to buy and sell goods.
Robertson says live entertainment at Fort Frederick's market fair adds to the desired 18th-century ambiance.
"A real, 18th-century fair wouldn't be just about the buying and selling, but largely about the entertainment aspect," he says.
So visitors will find slack-rope walking and juggling by Signora Bella and music, magic and comedy by Faire Wynds.
Although the intention of the fair is to provide a historically accurate portrait of life at the fort in the 18th century, park historians says that it is important to remember the original purpose of Fort Frederick.
"What people should consider is that we aren't doing something that necessarily would have been done here at Fort Frederick back then, being too far away from the metropolitan areas," Robertson explains. "But what better place today to hold an 18th-century fair than here, since it is so well-preserved and has so few modern intrusions."
There will be more than 150 period vendors, known as sutlers, at the fair. Some are local, but many travel here each year. Regina Albert from Delaware will be operating a period bake oven. Neil Redman from Little Orleans, Md., will be selling handmade 18th-century-style clothing.
For families and children, the market fair can be a learning experience with a variety of activities.
Bob Yetter, a French and Indian War re-enactor from Gaithersburg, Md., who has been involved with the market fair for 12 years, points out that the fair also caters to another demographic.
"It's a massive mall for re-enactors," explains Yetter. "You can find any wares you might need for your re-enacting throughout the year - weaponry, clothing, food stuffs, anything."
And Yetter should know. In addition to re-enacting, his primary job at the fair is judging the sutlers on the quality and accuracy of their goods.
"I make sure they are valid re-creations of authentic 18th century items," he says.
Like Yetter, those with a passion for local history will come to Fort Frederick's Market Fair to deepen their appreciation, as well as instill the love of history in others.
Since Yetter is primarily a French and Indian War re-enactor, his fondness for Fort Frederick makes sense - the fort is an educational center for the study of the French and Indian War.
"The French and Indian War is when America started to be America," Yetter says. "The seeds of our independence were sown, and we really started to get a sense of unique identity."
Yetter will speak at the fair about the French and Indian War as well as Fort Frederick's role in the war.
If you go ...
WHAT: 14th annual 18th Century Market Fair
WHEN: Today through Sunday, April 27; open from 9 a.m. to 5 p.m. today through Saturday and 9 a.m. to 3 p.m. Sunday.
WHERE: Fort Frederick State Park, Big Pool, Md.
COST: Admission is $4 a person, free for ages 6 and younger.
CONTACT: Fort Frederick State Park, 301-842-2155 or go to www.friendsoffortfrederick.info/market_fair.htm