In Al Hanissim we mention a Yochanan Kohen Gadol. Since there were several kohanim gedolim named Yochanan which one is this, historically?
It's not so straightforward to assume that the Yochanan Kohen Gadol of (Ve')Al Hanissim is the same one who became a Tzeduki. The Vilna Gaon (Imrei Noam to Berachos 29a) distinguishes them (and Josephus' account supports this): the latter was Matisyahu's grandson; the former is obviously, from the wording of the prayer, Matisyahu's father.
Yochanan Kohen Gadol served for 80 years and he became a Tzeduki in the end!
Per Abaye: Yanai Ha'Melech was Yochanan Kohen Gadol.
Per Rava: They were different people. Yanai was a Rasha from the beginning, Yochanan was initially a Tzadik.
There are three options. The famous Yochanan kohein gadol was either the father of Matisyahu, or his son, or his grandson. http://www.torahmusings.com/2006/01/yohanan-high-priest/