Hazel Jones-Olszewski, an 84-year-old widow who died just four days before her 85th birthday in January 2013, left the Church in Wales in shock after they learnt that she bequeathed more than $4 million (£2.6 million) to the St. Davids Parish Church, which she attended as a child in the village of Saron, Wales.
Church spokesman David Hammond Williams told BBC that the church was "very grateful" for the money and described it as a "once in a lifetime" opportunity for the diocese.
Jones-Olszewski, who had outlived two husbands, left Saron in 1991 to live with her son, Stansfield, in Chelsea before moving to a home for the elderly in Kensington in 2009, according to an obituary provided by The Diocese of St. Davids.
"This is a family tribute to an ordinary Welsh woman who did an extraordinary deed in wanting people in the diocese of St Davids to benefit after her death," said a message at the top of the obituary.
Villagers in Saron told Mail Online that they were surprised by Jones-Olszewski's donation to the church because they had no idea she was so wealthy.
"She came from a good family but they were by no means wealthy," said one villager who didn't want to be identified.
"She was a very likeable, ordinary woman when she lived here and it came as quite a shock when we found out how much she had left."
Locals however speculated that the fortune could have been accumulated from the estates of her two husbands as well as her son who died shortly after she moved in a home for the elderly.
"It is a vast amount of money for someone who started life with very little," said one villager who knew the widow.
"I don't think people are concerned how she came by it, they are just delighted she left it to the church and it will go to the people who she thought deserved it," the villager added.
The widow requested in her will that her gift should serve as a lasting memorial and shared throughout the St. Davids Diocese according to Mail Online. The church is expected to memorialize her with a plaque while half the money will be invested in youth projects as well as training for clergy and lay ministers.
The church has invited suggestions on how the money should be used. Jones-Olszewek was buried beside her son in Gunnersbury Cemetery, West London.