Presumption of priestly descent

The presumption of priestly descent in Judaism is the attribution to a kohen of equivalent position as if there was proven descent from the priestly family of Aaron. This is evidenced not by genealogical records but by de facto priestly behaviour as defined in rabbinical halakhic texts.In the Land of Israel it was the raising up of hands in the priestly benediction, and sharing heave-offering at the threshing floor, whereas in Syria and Babylonia the raising up of hands constituted adequate grounds, but not sharing heave offering at the threshing floor as stated in the Jerusalem Talmud Ketubot 2:7 and other texts.The ""presumed kohen"" kohen mukhzaq (Hebrew: כהן מוחזק‎, from חזק) is a Rabbinic title which legitimates Kohen status to a Jewish kohen who—amongst multiple criteria—exhibits conduct exemplary of and is recognized by his peers and community as such.The tannaitic rabbi Jose ben Halafta extolled the soundness of the said ""presumption"" (chazakah) by calling it a basis for the entire halakhic concept of chazakah (B.Ketubot 24b). It is based on this presumption that all Poskim agree, unanimously, to forbid presumptive Kohanim from marrying a divorcee. Of note is that from amongst the opinions of the Achronim, the mentioned presumption is given the title ""a sound presumption"".According to Maimonides, once he is established as a presumptive kohen it is a commandment to sanctify the Kohen. and assist him in abstaining from the prohibitions that apply to a Kohen. Maimonides considered that presumption of the Kohen is deemed valid and in good standing unless a valid objection to his lineage is made before a Beit Din.