Once widely regarded as the world’s richest and most powerful art collector, Sheikh Saud bin Mohammed Al-Thani of Qatar died suddenly at his home in London on November 9, age 48. Details of his death have not been announced, although initial reports say it was from natural causes.

A cousin of the Qatar’s current Emir, Sheikh Al-Thani served as the country’s president of the National Council for Culture, Arts and Heritage, from 1997 to 2005. During his tenure, he oversaw the development of the oil-rich nation’s ambitious plans to build an extensive network of new schools, libraries, and museums. He also spent well over $1 billion on art purchases during that period, more than any other individual, according to many art-market observers.

Qatar’s royal family is known for its prodigious collecting habits, ranging from ancient manuscripts to contemporary art. Over the past two decades, Sheikh Al-Thani acquired a vast collection of art and artifacts, with a special concentration on historical pieces, including Islamic ceramics, textiles, scientific instruments and jewelry.

His collection makes up the bulk of holdings in five existing and planned museums: the Museum of Islamic Art, the National Library, the Natural History Museum, a Photography Museum, and a museum for traditional textiles and clothing.

Sheikh Al-Thani was also a major collector of vintage cars, bicycles, antique furniture, and Chinese antiquities.

In 2005, he was dismissed from his post and circumstances surrounding his purchases and holdings were investigated. Relatives accused him of embezzling millions from family members and misappropriating public funds. He was cleared of wrong-doing shortly after, however, and returned to his position as a major player in the international blue-chip art market.