Complex sentence: In 1678, when Malvasia publishes his history of painting in Bologna:'Felsina Pittrice', he includes a transcript of a letter, which he claimed to have seen, sent from Raphael in Rome in 1508 to his friend Francesco Francia in Bologna.
Split into simpler sentences: In 1678, when Malvasia published a history of painting in Bologna titled "Felsina Pittrice", he included a transcript of a letter which he claimed to have seen. This letter was sent from Raphael in Rome in 1508 to his friend Francesco Francia in Bologna.