The Zohar (in Chelek Beis, pg 78b) writes that Yakov Avinu took the months of Nissan and Iyar for himself (hence Yetziyas Mitzrayim, Kabbalas Hatorah), and Eisav took the months of Tammuz and Av for himself (and hence, the 17th of Tammuz and Tisha Be'av), but only the fir...