Giorgio Armani, a stalwart of Milan ready-to-wear who revolutionised fashion with unstructured looks, has died at the age of 91.

Armani died at home on Thursday, his fashion house said.

The fashion designer failed to appear at his runway shows in June as he was recovering from an undisclosed illness.

He was planning a major event to celebrate 50 years of his signature Giorgio Armani fashion house during Milan Fashion Week this month.

In the late 1970s, Giorgio Armani revolutionized the global fashion landscape by introducing Italian ready-to-wear outfits that featured an unlined jacket, basic trousers, and a subtle urban color scheme. This distinctive relaxed silhouette quickly became synonymous with the Armani brand, sustaining its influence for five decades.

Armani’s classic tailored designs, crafted from extremely soft fabrics and understated shades, adorned the affluent and well-known from corporate offices to Hollywood sets. His chic black tie ensembles and sparkling evening dresses were frequently the highlights of red carpet events during award seasons.

Upon his passing, Armani had amassed a vast empire valued at more than $US10 billion ($15.3 billion), extending beyond clothing to encompass a diverse range of accessories, home decor, fragrances, cosmetics, literature, floral arrangements, and even chocolates. This prolific expansion secured him a place among the world’s top 200 billionaires, as reported by Forbes.

The designer also owned several bars, clubs, restaurants and his own basketball team EA7 Emporio Armani Milan, better known as Olympia Milano.

Armani opened more than than 20 restaurants from Milan to Tokyo since 1998, and two hotels, one in Dubai in 2009 and another in Milan, in 2010.

Armani himself was the foundation of his style

The essence of Armani style was a reflection of Giorgio Armani himself, with his striking blue eyes, consistently tanned complexion, and prematurely gray hair. His signature attire of jeans and a T-shirt, along with the understated elegance of his private residences, further defined his personal brand.

Armani’s fashion vision was that of easygoing elegance where attention to detail made the difference.

“I create for real individuals. There’s no point in designing apparel and accessories that lack practicality,” Armani frequently remarked when describing his target market.

Beneath the designer’s charming smile and impeccably gentle demeanor lay a shrewd businessman who effectively transformed his creative prowess into a vast fashion empire. Known as Re Giorgio or King George in Italy, Armani remained the sovereign of his enterprise, never engaging in mergers or sales, always maintaining full control.

Born July 11, 1934, in Piacenza, a small town south of Milan, Armani dreamed of becoming a doctor before a part-time job as a window decorator in a Milan department store opened his eyes to the world of fashion.

In 1975, Armani and his partner Sergio Galeotti sold their Volkswagen for $US10,000 to start up their own menswear ready-to-wear label. Womenswear followed a year later.

The symbol of his new style was the liningless sports jacket, which was launched in the late 1970s and became an instant success from Hollywood to Wall Street. The designer paired the jacket with a simple T-shirt, an item of clothing he termed “the alpha and omega of the fashion alphabet”.

The Armani suit soon became a must in the closet of the well-heeled man. And for women, the introduction of the pantsuit in the executive workroom was all but revolutionary. Dubbed the “power suit” with its shoulder-padded jacket and man-tailored trousers, it became the trademark of the rising class of businesswomen in the 1980s.

Over the years Armani would soften the look with delicate detailing, luxurious fabrics and brighter shades for his basic beige and grey palette. His insistence on pants and jackets led some critics to label his fashion “androgynous”.