Origins of the Straw Hat [Time-Skip Spoilers]

[Nero D. Ace]

So, I've been reading the manga lately and here's my theory about it :-

The Straw Hat was given to Luffy by Shanks, who said that it was more dear to him than his life. The hat has no special "properties" that we know of so it must have more of an emotional significance than any other.

Now, Shanks is known to have been an apprentice on Roger's ship.

Also, in a new scene, Rayleigh (first-mate of Roger) commented that Luffy was growing into that Straw Hat.

Now, my theory is this -

The Straw Hat originally belonged to Roger and he gave it to Shanks after seeing the potential in him. After Roger died, Shanks continued his legacy with that hat and formed his own crew - The Red Haired Pirates. After meeting Luffy, he senses that he had the same spirit that Roger had and passed it on to him.

There's also the fact that in a recent scene, Rayleigh is first seen being asked by Roger to be his nakama and his appearance strikingly resembles that of Luffy, albeit with a mustache.