A modest mansion.

The only surviving plantation house in Southern Florida, Ellenton's Gamble Mansion reminds of the realities of antebellum life.

Passersby may identify Ellenton by one of its newest structures, the vast concrete outlet mall that rises on the edge of the interstate, but it's the oldest building in Ellenton, the genteel Gamble Mansion, that captures the true heart and history of this little town. Built as a sugar plantation in 1844 by Major Robert Gamble, it's a glimpse back to antebellum Florida and the early pioneers.

Gamble migrated here after the Second Seminole War opened up the area for settlement. A true entrepreneur, he envisioned growing vast sugarcane crops in the fertile soil and even operating a processing plant here. Gradually, he amassed 3,450 acres, with 1,500 under cultivation. To work the land, he shipped slaves down the Manatee River from his family's Tallahassee plantation.

The mansion, which includes a northern and southern section, is of classic Florida vernacular architecture, built not to make a statement but to accommodate the semi-tropical climate. Two-foot thick walls of red brick and tabby, an early concrete mixture of water, oyster shell and limestone, form the building's skin. The wall mass insulates efficiently, keeping hot air out, cool air in, and creating cooling shadows. The walls have weathered nearly a century and a half of Florida summers, but most of the timber has been replaced, with only some original pine roof beams and trusses remaining. Because it's situated quite a distance from the river, flood control was not an issue for the structure. It's ground-heavy, in fact, lying low on brick footings. The slightly raised floor with ventilation slits is actually a climatic concession, allowing air circulation and controlling dampness.

Gamble's fondness for Jeffersonian design in Virginia shows in the mansion's classical, Palladian facade and simple rectangular plan. Six load-bearing columns, two inner pairs and one flanking each corner, provide formal, symmetrical balance.

"It's really a mini-mansion," says Laura Lothrop, a Florida National Parks volunteer who leads tours of the mansion. "Gamble adapted classicism to fit a smaller scale. Actually, it's one room wide with a parallel corridor from one end to another."

The 18-column colonnade, running aside the mansion's periphery, supports the roof and upper verandas. Each load-bearing tabby column is 28 inches in diameter. Upstairs, wide eaves provide shade and efficient stormwater run-off.

The northern and oldest section of the mansion houses a kitchen and all-purpose work/storage area. This section is separated from the rest of the structure by a "dogtrot" or breezeway, a covered loggia-like corridor designed to funnel east-west breezes through the house. Gamble faced the mansion south, both to avoid the hot summer sun and to create an imposing vista for visitors as they arrived by boat.

Upstairs a vestibule with double doors opens onto the master bedroom, featuring pine floors and a grand fireplace. A notable element is the oak-leaf stencilled "floor cloth," a forerunner to linoleum. A durable, inexpensive covering, it was used widely in the 1800s. The double doors open up to the veranda and a sweeping view of the river.

The veranda, a worldwide staple of vernacular tropical architecture, creates shade and breezes. A socially prominent bachelor, Gamble entertained frequently in the evenings on the verandas, which functioned as outdoor rooms, perfect for gatherings of restrained elegance.

On such evenings, pine dining tables would be set with curiosities such as "pap bowls," delicate china receptacles catering to the needs of the toothless. Slaves would roll out a piano to entertain guests while they enjoyed cool breezes and the river view.

But that gracious lifestyle ended in 1856, when falling sugar prices and crop losses plunged Gamble into bankruptcy. He sold the entire estate for $190,000 to two men from Louisiana. "He was desperate to sell and get out," says Laura Lothrop.

In May 1865, Confederate Secretary of State Judah P. Benjamin hid in the mansion for a few days during his escape from Union forces. Posing as "Mr. Howard," he eventually escaped to England and became a member of the English bar. Today a Judah P. Benjamin Confederate Memorial on the grounds marks that visit.

Over the next decade, the property suffered through more hard times, and the mansion slid into disrepair. In 1872, Major George Patten bought the land and mansion for $3,000. Rather than undertake expensive repairs to the deteriorated structure, he built the Patten house. A classic example of the pioneer Florida farmhouse, it was of a single story with a timber frame and front veranda.

By the 1920s, the Gamble house was in a sad state. Armor Chemical Company had bought it and had been using it to store fertilizer -- all that "Gone with the Wind" romance degenerating into a toxic dump!

But in 1925, the Judah P. Benjamin Chapter of the United Daughters of the Confederacy came to the rescue, purchasing the property and deeding it to the State of Florida as an historic site. The mansion was placed on the Historic Register, paving the way for its subsequent restoration as the only surviving plantation house in the south of Florida.

Today the old plantation is surrounded by the urban reality of shopping centers, mobile homes and Lego-like housing developments, but the restored old buildings, shaded by towering oak trees and overlooking the flowing Manatee River, allow visitors the illusion of walking into a grander yet simpler time.

"You can just imagine Gamble standing on his front veranda, surveying all that he owned," says Lothrop. His proud vision endures today, in this gracious little estate.

The Gamble Plantation State Historic Site is at 3708 Patten Ave. in Ellenton. Take I-75 north from Sarasota, get off at exit 43, head west on 301 for about one mile. You'll see signs and a white picket fence on the right hand side of the road. [phone]. The mansion is open 8 a.m. - 5 p.m. Thurs.-Mon., closed Tuesdays and Wednesdays. Adults, $3; children 6-12, $1.50. Tours leave at 9:30 a.m., 10:30 a.m., 1, 2, 3 and 4 p.m.