Bearing the surname often (although not always) indicates that one's
patrilineal ancestors were
priests in the
Temple of Jerusalem. Although not all Kohenic lines stem from
Aaron, the brother of
Moses, he is generally regarded as the patriarch of the lineage and the first Kohen. A single such priest was known as a Kohen, and the hereditary caste descending from these priests is collectively known as the
Kohanim. As multiple languages were acquired through the
Jewish diaspora, the surname acquired dozens of
variants. Not all persons with related surnames are kohanim, and not all kohanim have related surnames. Some Kohanim have added a secondary appellation to their surname, so as to distinguish themselves from other Kohanim—such as
Cohen-Scali of Morocco, who trace their lineage to
Zadok, and Cohen-Maghari (Meguri) of Yemen, who trace their lineage to
Jehoiarib, one of the
priestly divisions. Being a Kohen imposes some limitations: by Jewish law a Kohen may not marry a divorced woman and may not marry a
proselyte (someone who converted to Judaism). Nor should an observant Kohen come into contact with the dead or enter a cemetery unless for the death of a close relative. An effort to test whether people named "Cohen" have a common genetic origin has been undertaken, using a
genealogical DNA test associated with the
Cohen Modal Haplotype (see
Y-chromosomal Aaron). Cohen is one of the four Samaritan last names that exist in the modern day. ==Variants and derivations==