Both Sasuke and Madara's Sharingan awakened/evolved after they

Strongest Mangekyou Sharingan in Naruto Ranked: Sasuke Uchiha, Indra Otsutsuki & More

Naruto: 8 Things That Make No Sense About Madara's Plan

Naruto's Rinnegan Explained: How Madara Unlocked Them And Their Powers

Strongest Uchiha in Naruto Ranked: Sasuke, Madara & More

Final Awaken of Sasuke? THE GOD EYES All Evolution of Sasuke's Eyes - BiliBili

Just realized that Madara was was able to use sharingan and rinnegan in the same time. #madarauchiha : r/Naruto

Strongest Uchiha in Naruto Ranked: Sasuke, Madara & More

The Mangekyou : r/Naruto

When did Sasuke awaken the double Tomoe Sharingan? - Quora

Both Sasuke and Madara's Sharingan awakened/evolved after they broke their bond with their best friends. I love this parallel. : r/Naruto

Does evolution of the sharingan + emotional amps make the Uchiha physically stronger? : r/Naruto

What If Itachi Got The Eternal Mangekyo Sharingan In Naruto?

Madara Teaches Sasuke how to use sharingan