What development in Europe help explain why the renaissance spread north from Italy?

- The rise of humanism, which emphasized the importance of individual achievement and the study of classical Greek and Roman literature and philosophy.

- The development of the printing press, which allowed for the rapid dissemination of ideas and knowledge.

- The growth of trade and commerce, which led to increased contact between different regions of Europe and the exchange of ideas and cultural influences.

- The rise of powerful nation-states, which provided patronage for the arts and encouraged the development of new artistic styles and techniques.

- The invention of oil paint which allowed painters to mix colours in a much wider range than before.

These factors all contributed to the spread of the Renaissance from Italy to the rest of Europe, where it flourished in the 15th and 16th centuries.