https://www.rbth.com/arts/333600-picasso-and-russia
5. Composer Igor Stravinsky
Sketch of Famous Composer Igor Stravinsky by Pablo Picasso.Bettmann/Getty Images
To prepare the sets and costumes for Parade, Picasso went to Rome, where he met Igor Stravinsky. They became friends, and their soon friendship evolved into professional collaboration when Picasso worked as a designer on Stravinsky’s ballet Pulcinella and painted several portraits of the musician. Stravinsky tried to take one of these with him to Switzerland, but border officials demanded to know what it was and refused to believe that it was a pencil drawing by a famous artist since it looked more like a blueprint. The composer agreed that Picasso’s work was indeed nothing more than a blueprint of his face. In the end, the portrait had to be sent by diplomatic mail through the British Embassy.