What's the "een" in Halloween?
1650s, from Late Latin sponsor "sponsor in baptism," in Latin "a surety, guarantee," from sponsus, past participle of spondere "give assurance, promise solemnly" (see spondee). Sense of "person who pays for a radio (or, after 1947, TV) program" is first recorded 1931. The verb is attested from 1884, "to favor or support;" commercial broadcasting sense is from 1931.
one who stands surety for another in the rite of Christian baptism. In the modern baptism of an infant or child the godparent or godparents make profession of faith for the person being baptized (the godchild) and assume an obligation to serve as proxies for the parents if the parents either are unable or neglect to provide for the religious training of the child, in fulfillment of baptismal promises. In churches mandating a sponsor only one godparent is required; two (in most churches, of different sex) are permitted. Many Protestant denominations permit but do not require godparents to join the infant's natural parents as sponsors. In the Roman Catholic Church godparents must be of the Catholic faith.