She described the moment as life-changing saying preserving Diana’s legacy is worth every penny.

“When you see them go for so little, you can’t not preserve them, if that makes any sense. Because we’re not rich. We’re not wealthy. This is all from donations. We always mortgage our house when we do this kind of stuff,” Plant told PEOPLE.

Plant continued that it was “maybe the third or fourth time” she and her husband, Livinio Stuyck Sanchez, had remortgaged their home.

Among the standout pieces she acquired were evening gowns by signature designers Elizabeth Emanuel and Catherine Walker—the latter now a firm favourite of Princess Kate.

The collection also included more than a dozen pairs of Diana’s shoes and the peach plume hat she famously wore during her honeymoon send-off with then-Prince Charles.

But the crown jewel of the collection was the floral Belville Sassoon dress, designed by David Sassoon, one of Britain’s most influential designers of the 20th century.

The bidding opened at $150,000 and climbed in $50,000 increments until it reached $350,000, before surging to its final sale price.

Diana wore the dress on several occasions, most notably during hospital visits where she sat with patients — moments that reflected her warmth and compassion.

The piece was affectionately dubbed the “Caring Dress” by Martin Nolan, co-founder and executive director of Julien’s Auctions.