GERSHOM MENDES SEIXAS, born in 1745 or 1746, was the product of what was then considered a ‘mixed marriage’: his father, Isaac, was born in Lisbon and became a merchant in New York and Newport; his mother, Rachel Levy, was of Ashkenazi background. Though apparently he received little formal education and remained throughout his life essentially an autodidact, he assumed responsibilities as minister at New York's Congregation Shearith Israel in 1768. His formal position as cantor involved responsibility for the worship services and preaching on special occasions. One such occasion was a service held upon the approach of the British fleet in New York Bay in August 1776, following a decision that the synagogue should close rather than continue to function under British rule. An unconfirmed tradition reports that he said this might be the last worship to be conducted in the almost fifty-year-old building on Mill Street, and that this address was delivered with such feeling and eloquence that ‘many of his listeners, we are told, were moved to tears by his pathetic words’.

Seixas fled from New York to Stamford, Connecticut, taking with him some of the Torah scrolls and sacred ceremonial objects from the synagogue. Four years later he was invited to Philadelphia, where a new Sephardi congregation, Mikveh Israel, was being established. At the dedication ceremony for the new building on 13 September 1782 he composed a special version of the traditional prayer said by Jews on behalf of the country in which they live. This invokes God's blessing and protection specifically upon

It also asks God's blessings upon those who were fighting in the American armed forces: