'His contributions to the world will live on': Tributes pour in for Microsoft co-founder Paul Allen

It's been announced that billionaire tech pioneer Paul Allen died on Monday from non-Hodgkin lymphoma

Tech leaders around the world have paid tribute to the industry pioneer and co-founder of Microsoft Paul Allen, with his childhood friend Bill Gates hailing him as being responsible for the existence of personal computing.

"I am heartbroken by the passing of one of my oldest and dearest friends, Paul Allen," Bill Gates said in a statement.

Allen died on Monday from complications from non-Hodgkin lymphoma at the age of 65.

He and Gates founded Microsoft in 1975, with Allen going on to serve as the company's executive VP of research and new product development until 1983.

He left and founded an investment company Vulcan, but remained a member of Microsoft's board and major shareholder until his cancer diagnosis in 2009.

An avid sports fan, Allen also owned the basketball team the Portland Trail Blazers and the NFL team the Seattle Seahawks.

Microsoft CEO Satya Nadella issued a statement on LinkedIn mourning the loss of Allen.

"Paul Allen's contributions to our company, our industry and to our community are indispensable.

"As co-founder of Microsoft, in his own quiet and persistent way, he created magical products, experiences and institutions, and in doing so, he changed the world.

"I have learned so much from him - his inquisitiveness, curiosity and push for high standards are something that will continue to inspire me and all of us at Microsoft.

"Our hearts are with Paul's family and loved ones. Rest in peace."

Apple CEO Tim Cook said "our world has lost a force for good", while Google CEO Sundar Pichai also highlighted Allen's philanthropic work, which is believed to have amounted to contributions of $2bn during his lifetime.

Despite Allen's close association with Microsoft and Bill Gates, his relationship with both were at times fractious.

In his 2011 personal memoir Idea Man, Allen suggested that his contributions at one of the most powerful corporations on Earth had been undervalued.

He claimed to have come up with the name Microsoft and with the idea to write a software program for the world's first micro-computer.

Controversially, he also accused Gates and former CEO Steve Ballmer of attempting to take ownership stakes from Allen's share of Microsoft while he was fighting cancer.

However, in an epilogue added to later 2012 editions of his memoir, Allen indicated that the pair had mended their friendship, while reflecting on the shared global legacy they'd created together:

"The history we share is more powerful than whatever comes between us."