secondary source

A secondary source is a later account that studies an event from the outside — written by someone who wasn't there, working from the traces the event left behind. Think of a historian's book about the French Revolution: the author never stood in a Paris street in 1789, but has read the letters, decrees, and newspapers of people who did, and woven them into a story that explains what happened and why. It sits one step removed from the event itself.

This matters because secondary sources are where raw evidence becomes understanding. A pile of old letters tells you little until someone gathers, compares, and interprets them — sorting the reliable from the doubtful, spotting patterns, and connecting causes to consequences. Most of what we casually "know" about the past actually reaches us this way: through textbooks, documentaries, and scholarly articles, not from the original documents.

The common trap is treating a secondary source as the plain truth, when it's really one historian's argument. Two careful scholars can read the same primary evidence and reach different conclusions, because every account is shaped by the questions asked and the era it was written in. So a good reader checks where a claim comes from — and remembers that today's secondary source can become tomorrow's primary one, when future historians study how our own age thought.