As well as the Mail, Rex also worked on its now-defunct sister weeklies the Hull Times, Yorkshire Times and the Lincolnshire Times.
Despite being born in Luton, Rex quickly became enthusiastic about the history as Hull after moving there to take a job at the Mail in 1969.
His widow Mavis, to whom he was married for 56 years, said: “Rex was a loving and caring husband at all times. He always put others before himself.
“He cared passionately about recording Hull’s history. Accuracy was very important. It needed to be right.
“He was always very interested in Hull and its history, so he was delighted when he was asked to take on Flashback. He never lost that interest in local history, even when we both retired.”
Rex continued to contribute to Flashback into his mid 70s, but lost his battle with motor neurone disease on 15 February.
Mavis added: “”It was people’s response to their history that Rex found so fascinating. Rex found that even when people left Hull, sometimes for the rest of their lives, they never really lost their connection with the city.
“He received correspondence and thanks from people all over the world, which was both a joy and a delight for Rex. In many ways, he became part of the families he was writing about.”
Former Mail journalist Roy Woodcock knew Rex for 40 years, having joined the Mail in 1973.
He said: “Rex was an old-school journalist. He was an excellent writer and sub-editor. He was also a great help to legions of young journalists who knew they could turn to Rex for advice. He was real gentleman and a real gentle man.
“People knew him as Mr Flashback. I suppose he became something of a local personality in his role editing the daily Flashback page in the Mail and the monthly Flashback publication.
“He was always happy to be known simply as Mr Flashback. He had such a wealth of knowledge and he loved to pass that on, especially to younger people. Rex was able to reignite friendships through Flashback and I know that gave him huge pleasure.”
Stuart Russell, who now edits Flashback, paid tribute to his predecessor.
He said: “Rex was a quiet, private man, but a journalist who was very thorough in everything he did.”
Rex is also survived by his two sons, Stephen, 50, and Philip, 48, and ten-year-old grandson Jack.
A service of celebration and thanksgiving for his life was held on Monday.