Excerpts from Books and Wikipedia
"The bombing of Guernica served no strategic purpose in the Spanish Civil War. Franco's real aim was to destroy Basque nationalism. . . . General Franco denied the attack; then he blamed the Basque themselves. But four foreign journalists were in the region, and the truth was soon out. World opinion was shocked. Certainly Picasso was horrified: his gory masterpiece was completed two months later." [Furtado: 1001 Days]