SAT Grammar Question

<p>In The Ultimate Guide to Sat Grammar, one sentence is: Some of the book's passages wonderfully describe the physical realities of the Middle Ages, while others reflect the dazzling debates that would later lead to the Renaissance.
The answer key states there's no error. Can someone please explain why it's correct? Shouldn't would be changed to will?</p>

<p>Why would it be changed to will? Will is strictly future tense, and the events described in the passage have already taken place, so would is completely and absolutely correct.</p>