Siege of the Inner Colonies

The Siege of the Inner Colonies was a series of engagements taking place in humanity's Inner colonies.

Battle
On June 1st, 2536, the Covenant Empire finally made their way into the Inner Colonies.

Numerous ships were pulled from their positions in the Outer Colonies to defend the Inner Colonies. Old ships, such as the, were refitted and brought back into service to supplement the remaining defense forces.

Early Battles
One of the earliest battles in the Inner colonies was the Battle of Camber. 5.5 million people were killed in the battle, and the planet was glassed. Actium would fall nearly a decade later, along with Skopje. In a rare moment, the colony of Ballast would come under attack and the UNSC would win.

The Fall of Reach
The Fall of Reach was one of the greatest defeats in the Human-Covenant war.

In 2552, the Covenant had discovered Reach. The Covenant initially landed on the planet with a smaller fleet, but it began to escalate as more and more combatants arrived on either side. Dozens of Inner Colony planets were bypassed by the Covenant Fleet attacking Reach. While Reach would end up being destroyed, a cruiser, the, would escape the destruction and begin the decisive Battle of Installation 04.

It can be presumed that even more inner Colonies survived, considering the next Covenant attack was Earth.

The Battle of Earth
After almost 27 years of war, Earth finally came under attack by the Prophet of Regret in late 2552. Earth's orbit would become the first area to be besieged, before the Prophet would move onto New Mombasa. The Prophet would then use slipspace to fast travel out of New Mombasa and to Installation 05. Other Covenant forces would eventually move onto Ross Island, Havana, Cleveland, and Pawa. When the Keyship carrying the Prophet of Truth and John-117 returned to Earth, his forces would use the crater created by Regret to dig up The Artifact. This artifact would eventually lead to Installation 00 and the end of the war.

Aftermath
The loss of many of the inner colonies had a severe impact on the remaining UEG. The loss of Tribute alone would have a severe economic impact. On top of this, the Inner colonies that were hit hard by glassing would take a some time to come back up to full health. Reach wouldn't become habitable until 2589.

June 1, 2536

 * The Inner Colonies is entered by the Covenant.

May 2545

 * The Battle of Actium begins.

June 2545

 * The Battle of Actium ends.

2547

 * The Battle of Skopje is fought.

July 2552

 * The Covenant Empire take down a communication relay on Reach, beginning the Fall of Reach.
 * Tribute is also attacked at the same time.

August 2552

 * The Fall of Reach ends with Reach's glassing.

October 2552

 * The Battle of Earth begins.
 * The Battle of Mare Erythraeum begins on Mars.

November 2552

 * The Battle of Earth ends.

Unknown

 * Camber is attacked at some point in between 2535 and 2552.
 * The Battle of Ballast takes place at some point between 2551 and 2552.