George and Martha Washington -- in the form of the now-famous $4.87 million Atheneum portraits by Gilbert Stuart -- slipped into town unanounced last Friday. "We just got a charter and went up and brought them back," said Smithsonian Secretary S. Dillon Ripley yesterday. "They snuck in very quietly. It was no big deal."

The paintings had been expected here later this week, but, according to a Smithsonian spokesperson, were moved early to avoid any risk posed by public exposure of the transfer.

The departure of the paintings from Boston has stirred controversy ever since the National Portrait Gallery offered their owners, the Boston Atheneum, $5 million for the 184-year-old pair over a year ago. They are the only extant portraits of the Washingtons painted from life, and have hung in the Boston museum since 1876.

Recently, after a bitter battle to keep the paintings, led by an organization called Save Our Stuarts, the Boston museum and the Portrait Gallery came to a compromise. The paintings will alternate three-year stays at each institution. The portrait gallery paid $2.75 million, the Boston museum $2.125 million. The Atheneum lost $125,000 in the compromise.

Portrait Gallery director Marvin Sadik gave Smithsonian Regents a sneak preview of the Stuarts last night at the annual Regents' dinner, but the paintings will not be shown to the public for several weeks. "First we have to take them to the restoration lab and have a good look at them," Ripley said yesterday, adding that the question of cleaning would require "careful consideration. But we need to have them properly framed. The frames are now inappropriate -- old but not old enough."

The Stuarts are expected to be ready to receive viewers on July 4.