Beginning with climbing atop Nepal's Annapurna on April 23, Nirmal Purja, 36 reached the top of Shishapangma in China's Tibet region on Tuesday morning, the BBC reported.
Joining the British Army in 2003 and becoming a Royal Marine in 2009, Purja's climbing career began when he walked to Everest base camp in 2012 and then decided to climb the world's highest mountain.
Already the holder of numerous records - including the fastest "double-header" of two mountains higher than 8,000 metres - and awarded the MBE by the Queen in 2018, Pujra planned to break the record of conquering the world's 14 highest peaks
Purja's own website says the previous record holder was Polish climber Jerzy Kukucza, who finished the challenge in 1987 in 7 years, 11 months and 14 days, while an article on the British Mountaineering Council's website says the record holder was South Korean Kim Chang-ho, with a time of seven years, 10 months and six days.
After the Annapurna, Pujra conquered Dhaulagiri on May 12 and the Kanchenjunga on May 15, and climbed the Mount Everest on May 22.
During his climbs, he rescued four other climbers - three of whom he called "suicide missions" - and has, in his own words, "bled from every angle", the BBC said.
After Everest, he conquered the Lhotse the same day and Makalu on May 24 (both in Nepal), telling the BBC in August that he climbed the three peaks in five days, but it could have been three - had he not stopped for two nights "to have a drink".
Purja then headed to Pakistan where he climbed the Nanga Parbat (July 3), Gasherbrum 1, (July 15), Gasherbrum 2, (July 18), K2 (July 24), and the Broad Peak (July 26).
Climbing the Cho Oyu in China on September 23 and Manaslu in Nepal on September 27, he had to wait till he got permission from China for climbing Shishapangma, which came in mid-October after the Nepali government approached the Chinese government on his behalf.
( With inputs from IANS )