On Oct. 23, 2014, philanthropist Paul G. Allen donated $100 million to fight Ebola and called on the global community to join the cause.

Allen, a major donor since retiring after co-founding Microsoft, had been watching Ebola for years. Back in 2009 he funded a project at Kansas State University to adapt an Ebola vaccine for use with wild apes. Perhaps a third of African gorillas and chimpanzees have been killed by the Ebola virus since the 1990s, and these infections give the virus easier pathways to humans. So it is perhaps not surprising that Allen led philanthropic responses to the 2014 outbreak of the disease, saying “I am committed to doing my part in tackling this crisis…to prevent it from becoming a global epidemic.”

He helped convince other donors to contribute as well, including $50 million from the Gates Foundation, $25 million from Mark Zuckerberg, and other large and speedy gifts. The emergency operations director of the U.S. Centers for Disease Control later attributed the successful control of the 2014 Ebola outbreak in West Africa “to the huge contribution made by Paul Allen.” The almost instant speed with which Allen’s foundation delivered the money made it possible to dispatch 500 emergency health responders and all of their equipment to Liberia and two other countries where the disease was ravaging thousands.

Allen worked with the U.S. State Department and the World Health Organization to increase their capacity to coordinate the logistics required to transport international aid workers.