Riccardo Cassin, 100, pioneer on ascents of mountains

He was remembered Mr. Cassin as a man who helped to transform mountaineering from a romantic 19th-century challenge into a highly technical sport.

He was born into poverty in the northeast village of San Vito al Tagliamento. When he was a toddler, his father died in a mining accident.

As a young man, Mr. Cassin began work as a blacksmith in the town of Lecco on Lake Como. Sunday outings with friends in the mountains sparked his love for climbing over a six-decade career.

He and his companions were known as the Ragni di Lecco, “the Spiders of Lecco.’’ They went on to create daring routes that are used today to climb some of the most treacherous peaks.

The most memorable of Mr. Cassin’s first ascents included the 1961 climb up the previously “unclimbable’’ southern ridge of Alaska’s Mount McKinley, the highest peak of North America at 20,320 feet.

Mr. Cassin and his five companions received a congratulatory telegram from President John F. Kennedy after they conquered McKinley at the cost of severe frostbite. The most daunting McKinley ridge is named after Mr. Cassin.

He continued to climb until the late 1980s.