Wert, I love this stuff. My home town of course.
My understanding is that no one is sure who Catharine was. It is thought she may have been the wife of Capt. John Butler, commander of Butler's Rangers, a Loyalist Paramilitary group who's winter quarters were located in Niagara, or what is now Niagara-on-the-Lake. When Butlers Rangers disbanded many of its members settled the area. What is now St. Catharines was also called The Twelve, Murray's District and Shipman's corners, but was known as St. Catharines as early as 1796.
However W.H. (William Hamilton) Merritt did not name it after his wife after she died in 1796, as he was only born in 1793, as was his wife.
Here's a short but concise bio, which I'll also point out does not mention him being Post Master. That is not to say he wasn't, but I had never heard that before, and I've been know to be wrong WAY to many times.http://www.biographi.ca/en/bio/merr...1862_9E.html
He is however an incredibly interesting and important figure in the region history, his family name is everywhere.
As to the origin of the name of the city, I have a book called Names Across Niagara (John N. Jackson, Niagara Heritage Series, Vanwell Publishing 1989) which reads ;...the district town was to be located on land owned by George Hamilton, son of Robert Hamilton, the Queenston merchant whose wife is recalled in the name St. Catharines.' The district town they are referring to is Hamilton, of course, but I think it interesting they relate the name of St. Catharines to a specific person.
The book later states that 'St. Catharines is named after the daughter of John Askin and his Indian wife. Askin was a prominent Detroit merchant with close Montreal connections. Catharine, educated in a convent at Montreal, in 1778 married Samuel Robertson, the captain of an Upper Lakes sailing vessel. After his death in 1782, she married Robert Hamilton (remember him?) in 1784, gave birth to five sons and died in 1796.'
That may be were you got the date, Wert. The passage goes on about how Hamilton owned extensive tracts of land in St. Catharines, including a mill and warehouse, and gave land for the first church and school.
The book continues, 'The possibility of a name after the wife of either John Butler or Hamilton Merritt has been disavowed. Though confusing, the correct official spelling is now St. Catharines, though both the early post office (1817) and the later Grand Trunk Railway used St. Catherines.'
The book does mention the Cathedral dedicated to St. Catherine of Alexandria, but doesn't suggest it influenced the name, only adds to the confusion. Anyway, the cathedral was built in 1832, long after the town was named.
And Wert, I'm sorry to tell you that St. Catharines is NOT changing it's name back to the ER spelling. I easily found that story on the interweb, and it's published by the known satirical website, the Beaverton. Real FAKE NEWShttps://www.thebeaverton.com/2016/1...spell-right/
edit - I do see on the Canadian Canal Society website that he is listed as St. Catharines post master in 1840. So I do stand corrected. A very busy guy, ol' WH! Another website I just found says that his son Jedediah was post master for 18 years, starting in May of 1845.