To tell the story about how we - that is Michael and I - became friends with Juan Roberto Diago Durruthy, commonly known as  “Diago”, I have to tell it backwards.    The last time we saw him in Havana, in January of 2017, Diago started reminiscing. How long had we known each other? More than a dozen years, and much had changed. Now that he is an international star in the contemporary art world, he is represented by major galleries, and his works are included in international museum collections and featured by leading auction houses.