Lino Lacedelli, one of the first two climbers to reach the summit of K2, the world’s second-highest peak and among the most treacherous, died Nov. 20 in the house he had lived in since his birth in Cortina d’Ampezzo, Italy. He was 83.

His family said that he died of unspecified causes after a heart operation, according to Italian newspapers and broadcasters. Lacedelli and Achille Compagnoni reached the summit on July 31, 1954, and neither would say who was first. Compagnoni died in May at 94.

Reinhold Messner, a renowned Italian mountain climber, told the news agency ANSA that Lacedelli, conqueror of a peak regarded as more difficult than Everest by many climbers, was one of history’s “greatest climbers.”

The feat was not without controversy, something Lacedelli addressed in his 2004 book, “K2: The Price of Conquest.”

The events in question occurred the day before Lacedelli and Com- pagnoni reached the summit. They were being followed by Walter Bonatti and a porter, Amir Mahdi, who were carrying extra cylinders of oxygen.

When, around nightfall, Bonatti and Mahdi reached the site where they were supposed to meet the higher climbers, they were unable to locate the camp. Instead, it had been repositioned, beyond a dangerous traverse at a higher position. Bonatti accused Compagnoni and Lacedelli of choosing the less accessible site to thwart his summit attempt.

Bonatti and Mahdi spent a terrifying night in the cold and descended early the next morning. Compagnoni and Lacedelli retrieved the oxygen and made the summit.

Later, back in Italy, Compagnoni accused Bonatti of siphoning off oxygen from the sets. The dispute dragged on for years, with Compagnoni and Bonatti trading accusations. In his book, Lacedelli essentially supported Bonatti’s version. He said he and Compagnoni had deliberately failed to make their rendezvous, forcing Bonatti to abandon the ascent.