The Europa Champions League final was mired in controversy after one of Arsenal’s players declined to take part over fears for his and his family’s safety.
Henrikh Mkhitaryan, who is originally from the Armenian capital Yerevan, said although he had been reassured about his safety he decided not to travel with his teammates to Baku in Azerbaijan where they lost 4-1 to another English team, Chelsea.
Armenia and Azerbaijan do not have formal diplomatic relations and members of the Armenian minority often face persecution in Azerbaijan.
This is largely due to a protracted dispute over the Nagorno-Karabakh region which sits on their border.
How did the conflict start?
For much of the 19th century both Azerbaijan and the eastern part of Armenia were part of the Russian Empire. After the fall of Tsar Nicholas II in 1917 both briefly became independent countries before being absorbed into the communist system in 1921.
Following the collapse of the USSR as the separate republics broke free of Russian control Nagorno-Karabakh became officially part of Azerbaijan.
But in 1988 the majority Armenian population in the region started mass protests calling to be unified with Armenia.
What happened next?
In 1994 Azerbaijan and Armenia agreed a ceasefire brokered by Russia but there have been outbreaks of violence in the region.
In 2016 Azerbaijan sought to re-establish control of the area and claims to have recaptured 2,000 hectares of land.
Who controls Nagorno-Karabakh?
Although it is still officially part of Azerbaijan, the region is effectively self-run though it is dependent on the backing of Armenia and calls itself the Republic of Artsakh.
What do both sides say?
The European Azerbaijan Society wrote an opinion piece for Euronews in 2016 which said Nagoro-Karabakh is a puppet state controlled by Armenia and said Yerevan should abandon its “expansionist ambitions and concentrate on restoring its own fortunes so that it is no longer dependent on international handouts.”
But the Armenians have described Azerbaijan as its “former Soviet colonial master” and says it must recognise its independence in order to bring peace and security to the landlocked region.
Eduardo Lorenzo Ochoa from the European Friends of Armenia wrote for Euronews in 2016 that "(In) the early years of the Soviet regime the region of Nagorno-Karabakh was annexed to Azerbaijan as an autonomous region (oblast) upon Stalin’s arbitrary decision, disregarding the will of the people of Karabakh and its history.
"Nagorno-Karabakh initiated its secession from Azerbaijan through the adoption of Declaration of Independence on September 2, 1991.
"This act took place in full conformity with all the norms and principles of international law and the Soviet constitutional framework of that time, that granted oblasts the right to follow that path in a legally binding manner."
What does the international community say?
No country in the world formally recognises Artsakh as an independent nation and most international bodies still regard it as Azerbaijani territory but have called for a peaceful solution to the dispute.
In 2008, the United Nations General Assembly passed a non-binding resolution by 39 votes to 7, with 100 abstentions, recognising the region as Azerbaijani territory and calling for the withdrawal of Armenian troops.
In 2010, the European Parliament called for the withdrawal of Armenian forces from the region but said an international force should be sent to manage the territory while it goes through a transition period to solve the conflict.
The resolution "calls on the parties to intensify their peace talk efforts for the purpose of a settlement in the coming months, to show a more constructive attitude and to abandon preferences to perpetuate the status quo created by force and with no international legitimacy, creating in this way instability and prolonging the suffering of the war-affected populations; condemns the idea of a military solution and the heavy consequences of military force already used, and calls on both parties to avoid any further breaches of the 1994 ceasefire".