Put your research hat on—a new batch of archival material related to President Theodore Roosevelt just dropped. The Library of Congress has released a new online collection of several hundred thousand papers from T.R.'s tenure in public life, including his time before and after the White House, much of which had never been digitized before.

The Roosevelt project encompasses the largest collection of the former president's papers in the country, and one of the largest presidential collections at the Library of Congress in general. In total, it's made up of 276,000 documents, the bulk of which date from the period between 1878 and 1919. It includes, among other things, personal letters, official correspondence, diaries, notebooks, scrapbooks, and drafts of books, articles, and speeches.

Theodore Roosevelt speaks to navy servicemen in Massachusetts, 1902Library of Congress

Roosevelt gave a big chunk of his personal papers to the Library of Congress in 1917, just two years before his death in 1919. The former president was a history buff who had written a number of history books and biographies on American politics, and he was a big booster of the library during his presidency, so he was well-equipped to envision his archival legacy. He also had a personal friendship with longtime Librarian of Congress Herbert Putnam. Putnam promised that if the former president donated his papers while he was still alive, they would be kept locked within the Manuscript Division so that they wouldn't become public during his lifetime, a deal that Roosevelt agreed to. Over the decades, other donors have given the library even more records related to the former president, including his daughter Alice, who donated seven volumes of his diaries in 1958. While the collection doesn't represent a complete reckoning of Roosevelt's written records during his lifetime, it's a pretty thorough account.

Rough Rider muster roll, 1898Library of Congress

It includes the first written record of his use of the phrase "speak softly and carry a big stick," included in a 1900 letter to Henry Sprague of the Union League Club of New York, written while Roosevelt was governor of New York. It also includes letters to figures like Upton Sinclair, whom the president invited to the White House in March 1906 after reading The Jungle, his muckraking novel about meatpacking plants. There is also a roster for the Rough Riders, a campaign speech for his failed presidential run as a Progressive Party candidate in 1912, and other archival material from his life.

The collection comes online just in time for what would have been Roosevelt's 160th birthday on October 27, 2018. Explore it here.

Mental Floss just launched a new podcast with iHeartRadio called History Vs., and our first season is all about Theodore Roosevelt. Subscribe here!