The Nobel Peace Prize has been awarded to Colombian President Juan Manuel Santos for his ongoing efforts to end a five-decade-long civil war that has killed more than 200,000 people.

The prize came to Santos just days after Colombian voters by a slight margin rejected a landmark peace agreement that Santos had negotiated with rebel leaders, a significant blow to hopes for a lasting peace.

Here’s a look at why Santos won the prize and the impact of his achievements.

The 65-year-old Colombian president was recognized for tireless efforts to end the chronic violence that has gripped his South American country for decades.

The deal he helped negotiate would have given the rebel forces substantial inducements to join the political process.