Schoenberg and his followers—raised on the high Romanticism of composers like Mahler and Wolf—saw themselves as building on the Austro-Germanic tradition. At the same time, Schoenberg’s interest in painting indicates a close relationship between the Expressionism of artists such as Kokoschka and Kandinsky, and of his own music and that of his followers, such as Berg. Igor Stravinsky sprang to fame with his Russian ballets, such as The Firebird (1909) and The Rite of Spring (1913), and reinvigorated music with the primitive force of his rhythmic language, mirrored in the angular lines of the paintings of Picasso from the same period.
I've listened to The Firebird (1909) and The Rite of Spring each at least 9 times, but I know little about Picasso. So I don't understand the emboldened.