The timeline of the universe spanned billions of years. However, most of the Doctor's involvement seemed to be in what was sometimes called the Humanian Era, that part of history which encompassed human existence. As a result, the Doctor's TARDIS was most often seen between the time humans first evolved through to about the 85th century. Very occasionally the Doctor went further than the 85th century, into what might be called the "far future".
The Doctor was known to have visited, or at least been affected by, people and places in the following broad divisions of time as measured by at least one human dating system: