Timeline

A timeline was a method of ordering chronology, creating a history for an individual, place, event, etc.

Term
The term "timeline" was sometimes used interchangeably with other temporal terminology like "time stream." (AUDIO: Reborn) On two occasions, the Seventh Doctor pondered that Daleks would think twice before doing something to alter the timeline(TV: Remembrance of the Daleks) and the timestream. (PROSE: Transit)

Physics
Centering on what the Time Lords called the "primary timeline," (AUDIO: Reborn) alternate timelines could diverge, which if left unchecked would end the real universe millions of years before it was meant to. (PROSE: Blood Heat)

The Master and the Daleks manipulated and shifted "the timelines" to conquer Earth in 1921. (AUDIO: Master of the Daleks)

Universal History
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 82nd 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:


 * Pre-universe
 * Dark Times
 * Distant past
 * BC years
 * Far future
 * After-universe

However, his travels were usually known to have occurred at much more specific times. The Doctor and his companions were active in the following Earth centuries:  category=centuries namespace=14 ordermethod=sortkey shownamespace=false format=,\n* %TITLE%,, columns=4