Final answer:
The shift from Heian period's literary art to the martial and secular themes of the Kamakura period reflected the rise of the samurai class and the shifting balance between the aristocracy and warrior elite, enabling schools like the Kano school to thrive with new styles and grandeur.
Step-by-step explanation:
The changing priorities of secular patrons since the Heian era significantly influenced Japanese art of the Kamakura period. During the Heian period, the emergence of the samurai class laid the groundwork for a more militaristic and feudal society, which gradually shaped cultural expressions and artistic endeavors. The Kamakura period art reflected the balance between the traditional aristocracy and the rising class of warriors.
The legal system of the Bakufu became the foundation for ascendency and consequently influenced the rights and interests that were depicted in artwork. The Kano school flourished during this era, supported by shoguns and emperors. This new patronage encouraged the production of large-scale artworks with elaborate color and gold leaf, a marked departure from the previously dominant religious and literary themes of the Heian period. These changes in patronage led to innovations in art that echoed the societal shifts from courtly refinement towards martial prestige.