Dalek Empire

The Dalek Empire was a time and space-spanning empire created by the Daleks.

Origins
The Empire was formed during an unknown period in Dalek history, presumably after venturing into space from their home planet of Skaro. Events from this period may have included the initial attacks on Earth. (TV: The Dalek Invasion of Earth)

As the Daleks started understanding the abilities of their enemy the Doctor, they focused their efforts on creating their own means of time travel, eventually creating their own time machines. They attempted to hunt down the Doctor through time and space, but failed when the Doctor caught them in a rivalry with the Mechanoids. (TV: The Chase)

Expanding the Empire

 * As always, time travel makes the sequence of events here conjectural.

Settling down to more general use of their time travelling abilities, the Daleks proceeded on a grand effort to create a permanent base of operations. Using knowledge from the library of Kar-Charrat and the power of Gallifrey, the Daleks obliterated the entire Seriphia Galaxy, remaking it to their own designs. From there, the Daleks staged several major invasions of the Mutter's Spiral, notably in the 42nd and 67th centuries. (AUDIO: Dalek Empire (Big Finish))

Despite having their own galaxy, the Dalek Emperor maintained himself on the home planet of Skaro, and continued efforts from there to take over Earth at various points in history. (TV: The Daleks' Master Plan, The Evil of the Daleks, Day of the Daleks)

At some point the Daleks' creator Davros was re-animated (TV: Destiny of the Daleks) and returned to lead the Daleks, taking the role of Emperor for himself. (TV: Resurrection of the Daleks) A schism developed between the Imperial Daleks loyal to Davros and Renegade Daleks loyal to the Dalek Supreme. The subsequent Imperial-Renegade Dalek Civil War stretched across the entire Dalek Empire. Even as they waged war with each other, the Seventh Doctor seemed to have opposed and defeated both factions. (TV: Remembrance of the Daleks)

The Dalek Prime and Davros survived the war and encountered one another once more during a decline in Dalek pervasiveness throughout the galaxy. Davros was again defeated and the Dalek Prime set about rebuilding the Empire. (PROSE: War of the Daleks)

Last Great Time War and aftermath
United and re-unified once more, the Daleks, including Davros (TV: Journey's End) and a new Dalek Emperor (TV: Bad Wolf) fought the Time Lords in a titanic battle across all of history, resulting in the total destruction of both sides. (See the Last Great Time War.)

Several Daleks survived: The first was the Emperor, who built up a new army of Daleks from human genetic material, and unsuccessfully invaded Earth in the year 200,100. (TV: Bad Wolf, The Parting of the Ways)

The Cult of Skaro survived, consisting of Dalek Caan, Sec, Thay and Jast. An emergency temporal shift moved him to the early parts of the Last Great Time War, where he rescued Davros and brought him to the post-war reality. Once there, Davros swiftly constructed the New Dalek Empire. (TV:The Stolen Earth, Journey's End) Following the destruction of this empire, the survivors located a Progenitor device, and tricked the Eleventh Doctor into verifying them as Daleks. The device then created five new Daleks, who destroyed their forebears and escaped through a Time corridor to the 41st century, where they built yet another empire based on the New Dalek Paradigm. (TV: Victory of the Daleks)

Many other Daleks actually survived the Last Great Time War, as the Cult of Skaro found the Genesis Ark, a Time Lord artefact and prison which seemingly kept its prisoners safe from the Doctor's effort to finally end the war.

The third was a soldier that, according to the Ninth Doctor, "fell through time" and was captured and tortured by Van Statten. This Dalek absorbed Rose's DNA, downloaded and internet and was determined to continue the cause of the Daleks or re-establish contact with the Dalek Empire. The Dalek self-destructed when the Dalek realised it was mutating due to Rose's DNA.

Variant paths
Following their escape, the new Daleks discovered the lost Time Lord artefact, the Eye of Time, allowing them to alter time as they saw fit. The Daleks returned to Skaro, rebuilt their capital city of Kaalann, appointed a new Emperor, and began rebuilding their Empire. One of the Empire's first acts with their new-found power over time was to invade Earth in 1963. In this new timeline, they succeeded in killing every member of the human race. However, the Doctor and Amy Pond successfully undid these events, leaving Earth unconquered and erasing the new empire from existence. (GAME: City of the Daleks)