Koren's collection features documents, photographs and videos spanning four decades, and was transported by van from his home in the Dutch town of Hoensbroek to the IWGA headquarters in Lausanne.

It dates back to the founding of the World Games before its inaugural edition in Santa Clara, and includes the minutes of all IWGA General Assemblies and the final reports for all editions of the multi-sport event.

Welcome notes from American Presidents Ronald Reagan to Santa Clara 1981 and Joe Biden to last year's Games in Birmingham are part of the collection.

The IWGA plans to run a social media feature from March entitled "Way Back Wednesday" to share the history of the World Games with its followers.

Photo and video material has been available in an online archive for the 39 IWGA Member Federations and National Olympic Committees since 2020, in cooperation with the Olympic Channel.

IWGA chief executive Joachim Gossow explained the plans for the collection in Lausanne.

"We will sift through the material and digitise important pieces," the German official said.

"These include the Constitutions, which have been repeatedly adapted to the times and circumstances, as well as the final reports of host cities in the past and results books from those events.

"Again, we want to give our partners the opportunity to learn more about us and our development, or to research their own relationship with the IWGA."

IWGA President José Perurena thanked Koren for donating the material.

"We are aware that it is not easy to collect such an extensive documentation," the Spaniard said.

"We are well aware of our responsibilities.

"We want to use the material: our goal is to bring to light the path we have taken in the more than 40 years since the IWGA was founded in 1980.

"Co Koren's comprehensive documentation goes a long way towards that.

"We as IWGA are future-oriented and strive always to develop our product.

"But to stay on track on this path can only be secured by those who are aware of their roots and their past."

Koren, whose background is in the sport of tug-of-war, joined the IWGA Executive Committee in 1983, and was secretary general from 1989 until 2010.

He was named honorary life vice-president in 2010, and headed the Evaluation Commission for each Games up to Wrocław 2017.

The 12^th edition of the World Games is due to be held in the Chinese city of Chengdu in 2025.

The World Games is a multi-sport event for sports and disciplines not contested at the Olympics.