Joseph Rosati, CM (30 January 1789 – 25 September 1843) was an Italian-born Catholic missionary to the United States who served as the first Bishop of Saint Louis from 1826 to 1843.

Felix de Andreis, his friend and preceptor, advised Rosati to put aside Hebrew and take up English as he would need it in someday preaching in an English-speaking country.

[1] Dubourg himself returned to the United States on 4 September 1817, accompanied by a large group of priests and religious, also landing in Baltimore.

En route, they were joined by Donatien Olivier at Kaskaskia, where they crossed the Mississippi River to reach the former French colony of Ste.

Leaving De Andreis to help in the parish there, the group continued on to St. Louis, where they were shocked to find the church and rectory, built 40 years earlier, to be falling apart, totally unfurnished and not even having doors or windows.

[2] Pratte was able to tidy up and fix the rectory to a minimal standard of occupancy, just in time for the arrival of Dubourg and his entourage on 15 January 1815.

Rosati moved to Perryville, where he opened St. Mary of the Barrens Seminary in 1818, to educate the young men of the region and to train new members for the Vincentian Society.

After submitting a report on his diplomatic mission to the pope, he died in Rome in 1843, His remains were returned to St. Louis, and interred in his cathedral.

In a financial ledger from 1830–1839, Rosati recorded the sale of "my negro boy called Peter about nine or ten years old" to the Vincentian priest John Bouiller for the sum of $150.