Former Jedi Master Dooku was having a meeting with Jedi Master Sifo-Dyas on Coruscant about Order 66.
Sifo-Dyas thought that the order was just going to be a safeguard against the betrayal of rogue Jedi but he didn't know that Dooku was already a Sith Lord and the apprentice of Darth Sidious.
"Hello, my friend." Dooku said as he and Sifo-Dyas met and Sifo-Dyas nodded.
"Has the implementation of the inhibitor chips begun?" Sifo-Dyas asked.
Dooku nodded.
"I have convinced the Kaminoans to help implement the chips. Cloning will start soon." Dooku said.
"That's good news." Sifo-Dyas said.
Then Dooku noticed that Sifo-Dyas had a troubled look.
"What troubles you, my friend?" Dooku asked.
"I want to keep the Republic safe but is this really the only way?" Sifo-Dyas asked. "To have the clones execute the orders with these chips?"
Dooku then went up to Sifo-Dyas and placed a hand on his shoulder.
He really needed this project to happen for the downfall of the Jedi and for that, Sifo-Dyas should not hesistate.
"You must remember our mission." Dooku said. "The mission you started. It was to make a safeguard against the betrayal of rogue Jedi and to prepare ourselves for future wars. In time, the people of the galaxy will look to us as their saviors who prevented wars from happening before it was too late."
Sifo-Dyas then nodded.
"Very well. May the Force be with you." Sifo-Dyas said.
"And to you as well." Dooku replied.
After that, Dooku also met with the deadliest bounty hunter in the galaxy, Jango Fett, on one of the desert moons of Bogden.
"Jango Fett." Dooku said. "I have heard that you are the deadliest bounty hunter in the galaxy."
"What's the job?" Jango asked.
"I've selected you to be the clone template for a Grand Army of the Republic." Dooku said. "Imagine thousands of clone troopers all coming from you. How many men can claim such a legacy? And if you take the offer, a sizeable amount of credits will belong to you."
Jango then tilted his helmet, clearly considering.
"Hmm, the credits are good. But one thing. Why me? There's many other bounty hunters out there." Jango said.
"But you are different because you are of Mandalorian heritage." Dooku said. "That would make the clone troopers very hard to eliminate."
"Alright, deal." Jango said. "But I'm going to need something else."
"And what's that?" Dooku asked.
"My own clone." Jango replied. "With no genetic alterations."
"That can all be arranged." Dooku said as they shook hands.
Jango Fett would now be the prime template of the clone troopers.
Sometime later...
Later, Dooku met with his secret Sith Master, Darth Sidious.
"What news from the Kaminoans?" Sidious asked.
"The Kaminoans have created our clone army for our upcoming Clone Wars." Dooku replied. "And the chips were successfully implemented."
"Good. Good." Sidious said with an evil grin. "Now I have another task for you. Have the Pykes kill Sifo-Dyas. He has become too much of a liability now that the Jedi have started asking questions."
At first, Dooku felt a brief feeling of hesistation.
Sifo-Dyas was his best friend.
He was the only one besides him who knew that the Republic and the Jedi were becoming too corrupt.
On the other hand, he had risen so far and had so much power.
"Yes, my Lord." Dooku replied.
One day later, Dooku had ordered the Pykes to shoot down Sifo-Dyas' ship and a few minutes later, he received word of Sifo-Dyas' death.
This was how the clone troopers and Order 66 began.