London ? Sir John Soane loved the “poetry of architecture” and turned his house into his epitaph. More than a century and a half after his death, almost 100,000 people a year visit Soane’s eccentric, art-filled, lovingly preserved home on a leafy London square.

A Georgian town house filled with busts and bronzes, paintings and prints, a memorial to a pet dog and the coffin of an Egyptian king, Sir John Soane’s Museum is “one of the most magically romantic places in London, if not on Earth,” according to design consultant Stephen Bayley.

It’s also extremely crowded.

Curators are marking the 250th anniversary of Soane’s birth by giving the museum some much-needed breathing space, opening the Soane-designed house next door to the public for the first time.

Soane bought and rebuilt three houses on Lincoln’s Inn Fields between 1792 and 1824. He lived in the middle house, No. 13. When he died in 1837, he left it and its rich collection of art and antiquities to the nation on condition the house and collection remain unaltered.

That proviso has limited the museum’s ability to expand. Until recently, the museum owned only two of Soane’s three houses on the square. The third came up for sale in 1962, but the museum couldn’t raise the asking price of $16,000. It finally succeeded, $1.1 million, in 1996, and took possession in January.

The restored house at 14 Lincoln’s Inn Fields is due to open next year. It will contain an education center for children, some of Soane’s hundreds of architectural models, the museum’s collection of 9,000 architectural drawings by Robert Adam and “a room where people can just sit down and read books,” said curator Margaret Richardson.

Obsessive collector

It also will provide a new chance to appreciate the distinctive style of Soane, a bricklayer’s son who became architect of the Bank of England and London’s Dulwich Picture Gallery.

Sir John Soane's Museum at No.13 Lincoln's Inn Fields in London was designed by Soane, a British architect. As the 250th anniversary of Soane's birth approaches, museum curators are making plans to expand the crowded museum.

Inspired by classical Greece and Rome, Soane planned a series of grand projects for London, including a triumphal bridge and monumental government buildings. Many of his projects were never built; many that were have been destroyed.

Soane’s houses remain his most easily appreciated legacy. No. 14 Lincoln’s Inn Fields features the clean lines and an inventive use of space that made him a favorite of the early 20th-century modernists.

Richardson points out the airy starfish vault ceiling in the drawing room.

“The line is pure … this is the Soane that people started to like in the 1920s and ’30s,” she said. “People realized there was a link between modernism and Soane.”

Bayley said Soane “worked within the conventions of Georgian builders, but he soared beyond their limitations” with his original use of light and space.

Behind its classical facade, the museum delivers constant surprises — gravity-defying ceilings, hidden corners and hundreds of mirrors that provide unexpected glimpses of the objects on display.

An obsessive collector, Soane designed the house as a gallery for his collection and a classroom in which his students could view the glories of classical architecture.

The rooms are filled with Renaissance statues, Roman marbles and Greek vases. There are fragments of ancient buildings and architects’ models, and such artworks as Canaletto’s views of Venice and Hogarth’s 18th-century satirical masterpieces, “A Rake’s Progress” and “An Election.” And sunk in its own crypt is the 4,000-year-old limestone sarcophagus of the Egyptian Pharaoh Seti I.

At the back of the house, Soane installed a mock ruin, the grave of an imaginary hermit monk and the tomb — “Alas, Poor Fanny!” — of his wife’s pet dog.

The custodians have begun to restore these “outdoor rooms” — three courtyards that contain remnants of the medieval Palace of Westminster — and to rebuild Soane’s Pasticcio, a 30-foot tower of ancient and modern architectural fragments dismantled more than a century ago.

The Pasticcio is a typical Soane blend of playfulness and purpose.

Bayley said Soane’s collection “was there to inspire him, to inspire his students … he understood you should study the past so as not to repeat it.”