Laura Biagiotti, who helped transform her mother's business from a small tailoring shop in Rome to an internationally recognised ready-to-wear fashion brand, died on Friday aged 73, her family and company said.
Biagiotti died in hospital in the Italian capital where she had been in intensive care after a heart attack this week.
Born in 1943 at the height of World War Two, she studied literature and had wanted to become an archaeologist.
Instead, she decided to help her mother, whose small atelier had won a contract in 1964 for the flight attendant uniforms of flagcarrier Alitalia and soon after was commissioned to produce a collection for the US market by Seventh Avenue group.
Biagiotti designed clothes for stars including Ingrid Bergman and Bette Davis while working with stylist Emilio Federico Schuberth in the heady fashion years of the 1960s. She first presented her own ready-to-wear line in 1972 in Florence.
The business later opened its headquarters near Rome's Spanish Steps, where many fashion houses have their showrooms.
She launched a menswear line in 1987 and showed her creations using silk and cashmere in Beijing in 1988, when China was still mostly closed to the outside world.
Biagiotti often took inspiration from the Far East, with some of her most recent collections echoing Asian designs, and she became known as the Queen of Cashmere for her frequent use of that fabric.
The Biagiotti brand, one of the earliest internationally recognised fashion houses to be run by a woman, expanded to include accessories, glasses, children's and home collections, perfumes and sportswear.
In recent years, her daughter Lavinia, vice-chairman of the Biagiotti group, had been running the company, which moved its headquarters to a restored 11th century castle in the countryside east of Rome.
The elder Biagiotti adopted many abandoned dogs and looked after them in the castle's grounds.
In 2012, the company sponsored the restoration of the twin Baroque fountains in Rome's Piazza Farnese, joining other Italian fashion houses which have helped the cash-strapped government spruce up decaying monuments and cultural sites.