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 Tamuz and Av for himself (and hence, the 17th of Tamuz and Tisha Be'av), but only the first...