Nagato's Rinnengan were Madara's eyes and Tobi IS Izuna.

[JagiMagic]

I was asking the same question to myself but I think there might be someone else with the name Nagato, just like sasuke the third hokage's father,but there is no proof for that.
The only way that madara might know nagato is to see the future, coz nagato was't born when madara was alive.
Remember when 1-st and 2-nd hokages were alive the third hokage was just a little kid

 

[JagiMagic]

i only believe the fact that tobi is izuna about 65% but I don't believe that nagato's rinnengan were madara's eyes because that is impossible

 

[knowledge561]

Guys don't forget that Nagato is an Uzumaki. They tend to love long lives and Nagato and Konan were old when Naruto talked to them. Some of my theories have already been coming true. I predicted that Madara didn't die when Tobi stated he gave Nagato his eyes. Madara wanted to be revived for HIS plan of how to deal with the world. He and Tobi were in contact and he wanted Tobi and Nagato to team up in the future and continue his plan and revive him when things were ready. Madara and Tobi chose Nagato because he was an Uzumaki and would love long. He could've been a descendant of so6p and inherited the body so him getting rinnegan would be a great move as well for their plan. After Madara passed Tobi took everything into his own hands and flipped the script. He got power hungry and basically tried to rule Madara out and began making a name for himself using Madara as his Alias. When Kabuto showed him the Madara body when they met, he was shocked and in awe probably realizing that it wouldn't be a good idea if the Edo Madara realized how his plans turned out. Pretty much, Tobi ****ed him over because he wants to be ruler. I believe Madara was supposed to be revived and be ruler.