A rare piece of Cottesloe's history is on the market for the first time in 118 years.
And if the landmark residence dubbed Tukurua fetches anywhere near its reported value, it will become Perth's second highest house sale.
The property, on the corner of Marine Parade and Rosendo Street, is on a 5001sqm block and has a two-storey, 21-room limestone mansion with a sizeable portion of undeveloped beachfront land adjacent.
In a worldwide sales campaign, the home is being listed for sale by expressions of interest because selling agent Frank Torre, of House Real Estate, said there was little in Cottesloe on a similar scale with which to compare it.
"But nothing (in Cottesloe) has the development potential or the size of the house on it," he said. "We just don't know, it depends on what someone wants to do on it.
"They could keep the house or do a grouped dwelling."
Mr Torre said $10,000 per sqm was the most recent sales comparison, putting Tukurua's potential sale price at about $50 million.
That would be $7.5 million shy of Perth's and Australia's highest house sale record, when iron ore heiress Angela Bennett's Mosman Park home sold in December 2009 for $57.5 million.
Justin Davies, of Space Real Estate, has been selling Cottesloe homes for years.
He said Tukurua's massive landholding would help the property achieve a record sale price for Cottesloe.
He predicted that in the current market it could potentially fetch $7000 per sqm.
The 1896-built residence was the home of the late Dorothea Cass. Before that it was used as a summer residence by Septimus Burt, WA's first attorney-general.
Miss Cass inherited the home in 1945 after the death of her mother.
Her parents used Tukurua during World War II to house refugees from Singapore and returned servicemen.
Ted Smith inherited the home from Miss Cass after her death in 1994. She did not marry or have children.
Tukurua has been Mr Smith's home for more than half his life after he developed a close friendship with Miss Cass after migrating to WA from Ireland in 1968.
He met Miss Cass through friends and she asked him to water the gardens and live in a small cottage to help watch over the property.
Mr Smith said the friendship was never romantic and during their 22-year acquaintance they bonded over their studies at the University of WA - Miss Cass was one of the first women in WA to graduate with a bachelor of arts degree at UWA.
"She was a very religious person and she came to church with me," he said.
Mr Smith said he believed he inherited Tukurua because Miss Cass knew he would not "squander it".
From 2003 to 2009, he painstakingly brought it back to its former glory.