The bitter border conflict between Ethiopia and Eritrea, once a single nation, played out far from the global spotlight. Abiy's abrupt announcement last year, just weeks after taking office, that his country would fully embrace a peace deal revived hopes for an end to one of Africa's longest wars.
No one immediately knew whether the gesture of peace would be returned. Eritrea is one of the world's most closed-off nations, and longtime President Isaias Afwerki's response, if any, was mere speculation. Then, in another surprise, he accepted.
Here is a look at the conflict and its end. WHY WERE THEY FIGHTING? Eritrea gained independence from Ethiopia in 1993 after years of rebel warfare. Friction remained, especially along the border, which was never completely settled. In 1998 fighting broke out and raged for two years, ending with a peace deal that Ethiopia refused to accept. It rejected the agreement's handing of key border locations to Eritrea.
Nearly two decades of a no-peace-no-war situation followed, and Eritrea continued to withdraw into itself. WHAT HAPPENED LAST YEAR? Ethiopia early last year was weary from months of anti-government protests demanding greater freedoms from a repressive ruling coalition. When Prime Minister Hailemariam Desalegn resigned, a relatively little-known young leader took his place.
Abiy quickly surprised the country with a wave of reforms, but the gesture of peace to Eritrea was the most unexpected. For the first time in years, families long divided by the conflict dared to consider the possibility of seeing loved ones again. But how would Eritrea react?
Its leader, Isaias, appeared wary, noting "positive signals" and sending a rare delegation to "gauge current developments directly and in depth." Things picked up quickly from there. "We have tried war and found it useless," Abiy told his Eritrean visitors. "We want our brothers and sisters to come here and visit us as soon as possible."
Less than two weeks later, Abiy arrived in Eritrea's capital and was welcomed with hugs and laughter by Isaias, a joyous scene that was once unthinkable. Diplomatic, communication and transport ties would soon be restored, the leaders announced.
"We can assure you we will face the future together," Isaias said. "We will work as one." A week later he arrived in Ethiopia for the first time in 22 years, clasping his hands over his heart and addressing the crowd in Ethiopia's official language, Amharic. It surprised one longtime Eritrean colleague, who said he'd never heard Isaias speak it.
HAS ERITREA CHANGED, TOO? While communication and transport links remain open, border posts between Ethiopia and Eritrea didn't stay open long, and there is no sign that Ethiopia's reforms have infected its neighbor. The country remains tightly controlled and has not loosened the harsh system of military conscription that has led thousands of young people to flee.
But the war has ended, Ethiopia says, and some army units have been moved away from the border on its side. The two countries are said to still be working out the details of their new state of relations. Traffic and trade at the border, when it was open, was brisk.
Despite the warmth of last year's reunions and Abiy's meetings with Isaias since then, there was no comment from Eritrea's government on the Nobel Peace Prize, even though the committee noted its leader's role: "Peace does not arise from the actions of one party alone. When Prime Minister Abiy reached out his hand, President Afwerki grasped it," the Nobel committee said.
The only comment appeared to come from Eritrea's ambassador to Japan, who tweeted congratulations and added: "People of #Eritrea & #Ethiopia with blood, sweat & tears have won again over evil."
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