The [NYTimes Archive](http://www.nytimes.com/ref/membercenter/nytarchive.html) goes back to 1851.

[Here's](http://www.nytimes.com/1864/07/23/news/the-president-and-peace.html) a random example, showing that the articles are machine readable.

They also have an [API](http://developer.nytimes.com/docs/read/article_search_api_v2) for developers.

And they have an N-gram tool called [Chronicle][1]) where you can click on the results to view each article.

![enter image description here][2]


  [1]: http://chronicle.nytlabs.com/?keyword=Great%20War.World%20War%20I
  [2]: https://i.sstatic.net/GsGh3.png