When the institution of the synagogue began to emerge, the Temple in Jerusalem was still standing. The first roles of the synagogue were not associated with prayer, but rather with Jewish study and gathering. The first rabbis were not celebrants of religious rites but teachers of religious texts; in fact, the word rabbi means "my teacher".
Following the destruction of the Temple in 70 CE, the synagogue assumed an additional role as the place of communal prayer. No distinct architectural forms for synagogue buildings became standard, but the interior design came to include features still found today: a lectern for the leader of the service, a "Holy Ark" in which Torah scrolls are kept, and seating arranged facing Jerusalem, in honor of the centrality of the site of the former Temple.
As the liturgy evolved and became formalized, expertise in recitation was needed, since it was done by memory prior to the development of movable type and the wide-scale production of books. The knowledgeable person leading the congregation in prayer was considered its representative—in Hebrew, sh'liach tzibbur. Initially filled by an ordinary lay person with greater knowledge, the role developed over time into a profession, the cantor or hazzan.
The contemporary hazzan no longer needs to memorize the words of the prayer service, but is an expert in the musical rendition of the service. She or he has expertise in the diverse, historic musical traditions of the Jewish people and keeps abreast of new compositions for synagogue use. A cantor may serve as an educator for the community, and will often train children and adults in the musical tradition, either in preparation for becoming Bar or Bat Mitzvah or to participate in a choir during services.