Final answer:
The Crusades spread Renaissance ideas by facilitating the expansion of trade routes and the movement of goods such as silk and sugar, as well as through the transfer of ancient Greek and Roman knowledge by Byzantine scholars escaping to Europe.
Step-by-step explanation:
The Crusades contributed to the spread of Renaissance ideas throughout Europe mainly in two ways: through increased trade and the transfer of knowledge and culture. Firstly, the Crusades stimulated trade by establishing new trade routes, especially in northern and eastern Europe. This expansion led to the economic prosperity of regions like the Italian city-states, where trade routes connected Europe to the rest of the world, including the Middle East. Merchants returning from the Crusades brought back goods like silk and sugar, but also ideas and knowledge.
Secondly, the Crusades played a crucial role in the transfer of culture and knowledge. Byzantine scholars fled to Europe, carrying with them the preserved knowledge of ancient Greece and Rome. This included complete works of Plato and translations of Aristotle's works in the original Greek, which were pivotal in sparking the Renaissance philosophical and cultural revival. The intellectual richness these texts provided contributed greatly to the humanist movements that characterized the Renaissance. Moreover, the Crusades' influence remained in the European imagination, further shaping the thinking and ideologies of the time.