Madara is by far the strongest. If Itachi was stronger he would've killed madara himself.
idoshen, known as Idoshen Uchiha, is the brother of Madara. He is also the father of idashi uchiha. Idoshen was truly killed by his older bother madara. but rencarnated his powers in to his son known as idashi madara has only about 10 percent of his sharingan. basically idashi has two sharingans his own and his fathers.
They are equal in strengh
Well that depends when you say madara if you mean Tobi then yes he was afraid of itachi.
tobi(obito uchiha with Madara Uchiha soul )
Idashi Uchiha made no (Public) appearences in Naruto Manga/Anime or Naruto Shippuden Manga/Anime. Idashi appeared in the story after Manga Chapter 250 of the Naruto Childhood series (Which Never aired to the public) . at some point of that duration Naruto fought Idashi to see who would be stronger and it turned out they were equal in terms of Strength.
Madara. Not only does he have the eternal Mangekyou Sharingan, he has the Rinnegan too, as well as the implanted cells from Hashirama Senju.
Uchiha Madara, of course. He is one of the strongest (if not THE strongest) members of the Uchiha Clan. Since the Uchiha Clan is considered as a powerful clan, it is quite safe to say that Madara can stand up against the likes of Deidara.
Probably Uchiha Madara
He is one of the strongest however Madara Uchiha could be stronger.
Sasuke Uchiha and Madara Uchiha
Sorry madara fans but itachi is stronger than madara because if you read the comic or even watch the shows you would after itachi death madara said that if itachi know that he know this much information he would already kill him watch it you would know
Madara uchiha is much stronger than shisuia uchiha seeing that he has a permanant mangekyo sharingan and that he is the clan leader of the uchiha clanSO.madara uchiha could beat up shisui uchiha blindfolded, ha-not really, but madara uchiha could actually beat up shisui uchiha if they had a fightumm actually u would have to remember Shisui's mangekyou had the power of mind control and also he is know as "Shisui the Body Flicker" his speed jutsu menipulation is equall to of what madara uchiha used with his time space jusutu but yet even with that madara was born of a god a tengu a konoha tengu "madara's father" and his mother being a hyuga with the orginalization of the kekkegankai in volume 9 of naruto they speak of how every eye kekkegankai originated with the hyuga wich with these facts prove is true but back to the point thing is i think that they would be at a stand still.p.s. if u want more info look me up on imvu lUchihaShisuil ;D