User blog comment:Assassin of persia/So those were left for Ezio/@comment-2.26.76.19-20110623195841

I believe that at first when Ezio went to Masyaf he did not have the Hidden Blade, then he went to constantinople to look for the seals and was given one by Yusuf. He then (in the demo) went to Masyaf again. In the E3 cinematic trailer this is before he went to Constantinople.