In his eloquent autobiographies, abolitionist leader Frederick Douglass described the cruelty he experienced as an African-American slave in Maryland during the early 19th century. But Douglass' descriptions may have been missing some important details about the richness of slave culture at the time.
In a greenhouse on a centuries-old estate where Douglass lived as a young boy, archaeologists have dug up a variety of both mundane objects and strategically placed symbols of spirituality. These artifacts show for the first time that slaves lived in the greenhouse and that they sustained African religious traditions, even as they probably outwardly practiced Christianity.
By analyzing grains of fossilized pollen from the site, researchers were also able to show that the slaves used a corner of the greenhouse to experiment with plants for food, medicinal and household purposes -- beginning what would become an African-American gardening tradition.
Together, the wealth of new discoveries paints the broadest picture yet of the people who slaved away on a well-known plantation for centuries.
"African-American religion in the form of African traditions gave this building a second identity, one that was not described or not known by Douglass," said Mark Leone, an archaeologist at the University of Maryland, College Park.
"This is African-American culture here, both in terms of religion and agriculture, that has traditions that are still alive today," he said. "There was a whole set of concepts, ideas and practices that kept the community whole. That isn't something that could be destroyed through brutality."
The greenhouse, known as the Wye Orangery, was built in 1785. Today, it is famous for its architectural beauty, its rarity and its notable history. It is the only 18th-century greenhouse that remains in North America.
It sits on a plantation, which was founded on Maryland's Eastern Shore by the Lloyd family in the 1650s and has been passed down through nearly a dozen generations of the same family since.
The plantation has been immortalized by the writings of Frederick Douglass, who lived there for a few years around the age of seven.
In his 1845 book "Narrative of the Life of Frederick Douglass," the author, an ex-slave and famous orator and abolitionist, describes his time on the Lloyd plantation as full of fear and outrage. With horror, the young Douglass witnessed beatings and bloody whippings.
Now more than 150 years later, Leone and colleagues are trying to gain a deeper understanding of the slaves who kept the plantation running. For six years, the researchers have been digging on the land and probing its buildings.
In their latest endeavor, they plunged into the greenhouse. As well known as the structure is, its secrets have been long hidden.
"This building has always been known to be a greenhouse and anybody could guess that slaves probably ran the heating system, but nobody could tell if slaves lived in the building or what they did beyond stoking the fire and being the laborers for the enormous surrounding garden," Leone said. "That was how we started."
As they dug below a north-facing back room, the researchers found dishes, teacups, cutlery, buttons and other objects. Those objects identified the area as a slave quarter that was occupied between about 1785 and 1820.
About two inches beneath the doorstep outside the quarter's threshold, they also discovered two projectile points and a coin -- signature objects used in African religious traditions to control the coming and going of spirits.
Inside, they found another religious symbol: A stone pestle mortared into the framework of the furnace by the slaves who built it.
In addition to the religious and everyday objects, the researchers were able to document an extensive series of agricultural trials conducted by the slaves who lived there.
Their experiments began with medicinal plants, including Seneca snakeroot, ginger root and buckbean. They also grew broccoli, bananas and wild greens, as well as shrubs and flowering plants.
By the 1820s, they were cultivating more exotic plants, including lemon and orange trees, irises, lilies and members of the rose and nightshade families. As they labored with seeds and clippings, the slaves gained a wealth of gardening knowledge that they held onto as they gained freedom and left the plantations.
Most studies of plantation greenhouses have focused on the physical layout of the buildings and the kinds of plants that grew there, said Christa Beranek, an archaeologist at the University of Massachusetts, Boston, who has been excavating an 1806 greenhouse in Massachusetts.
By considering the laborers who kept these buildings humming, she said, the new study adds depth to our understanding of the era's greenhouses. In the late 1700s, greenhouses were still relatively rare possessions of elite plantation owners.
There were no manuals for how best to run them. Botanical knowledge came through experimentation and word of mouth.
"The kind of labor it took to run these greenhouses really was constant and very specialized," Beranek said. "As people working in greenhouses gained information on how to care for these plants and build specific structures, they learned what worked and what didn't. The body of specialized knowledge they were amassing might then get shared orally."