Great Jedi Purge

The Great Jedi Purge, also known as the Second Jedi Purge and Palpatine's Purge, was a major galaxy-wide military campaign carried out by the Galactic Empire and the Order of the Sith Lords. It was a galaxy-wide conflict which saught to root out and exterminate all the Jedi who had survived Order 66 and execute them and destroy the remnants of the Jedi Order.

The purge officially began in the year 19 BBY at the end of the Clone Wars with Palpatine giving out the order to all Clone soldiers to execute their Jedi commanders and Operation Knightfall which lead to the destruction of the Jedi Order. Despite the success at first however, around two hundred Jedi had survived Order 66 and Palpatine had concidered them a threat to the point of initiating the purge to wipe them all out.

Background
The purge officially began in 19 BBY after Chancellor Palpatine was revealed to have been the dark lord of the sith, Darth Sidious, all along and so, Jedi Master Mace Windu and three other members of the Jedi High Council had went in to arrest him. While Palpatine had succeeded in killing three of the four council members at first, Mace Windu had overwhelmed him and was soon defeated after Anakin came in and cut off Windu's hand giving Palpatine the chance to kill him. Afterwards, Sidious had made Anakin his new apprentice and dubbed him as Darth Vader and would send him out to the Jedi Temple to eradicate the Jedi Order and kill every single member of the order along with the help of a large detacthment of 501st Clones.

Operation Knightfall
After Anakin had became Darth Vader, Palpatine had given out the command to all Clone forces across the galaxy to execute Order 66 and have all Jedi Commanders killed. Across the galaxy, the order had been carried out and countless Jedi Commanders were killed by their clone soldiers. Back on Coruscant, Vader and the 501st Legion, had marched into the Jedi Temple and raided it. There, they systematically killed every single Jedi Knight, Master, and Padawan that was present as well as the temple security forces. The operation was a major success as it lead to the complete destruction of the Jedi Order with most of its members dead and its council dissolved. Afterwards, a beacon was activated to trick all Jedi Knights who survived Order 66 to return to the temple believing that it was safe but, it was a trap set up to lure them in and have them be killed by the Clone soldiers that were stationed there.

Decleration of a New Order
After Operation Knightfall was carried out, Palpatine had addressed the Galactic Senate where he gave a speech talking about how the Jedi had conspired to have him assassinated and that they were the enemies of the Galactic Republic. He fabricated the truth that his attempted arrest was a coup made against the Republic by the Jedi and that now that they were traitors, he would have them hunted down and executed for their crimes. He then declared a new order where he officiall dissolved the Galactic Republic and instead, he reformed it into the Galactic Empire for the security of the galaxy and its people. He was then greated with roaring applause and cheers and thus, the Empire was established and the Great Jedi Purge had begun.

Conclave on Kessel
One month after the execution of Order 66 and the downfall of the Jedi, around two hundred Jedi had survived and went into hiding. Palpatine, unwilling to allow the remnants of the Jedi Order to remain active, had sent out Imperial Soldiers and his apprentice, Darth Vader, to hunt down the survivng Jedi and have them killed. On the planet of Kessel, a group of Jedi who survived Order 66 had gathered in an abandoned mine where Jedi Knight Shadday Potkin had called for the creation of a Jedi conclave on the planet. Many survivng Jedi had gathered and there, they had discussed the Imperial campaign to wipe them out and what should they do about it.