I don't know which saint took the longest to be canonized but St. Joan of Arc must be close to the record. It took her nearly 450 years to be elevated to the altars. There are several candidates for sainthood who have been waiting even longer for their cases to be completed.
She was 28 when her canonization took place, which was only 4 years after her death.
Your dad
It took about 458 years after Joan died before she was declared a saint.
It takes a long time for any saint to be canonized. They have to go through a very lengthy process of beatification and cononization. Not to mention the universal church probably did not view her the way French Catholics did for quite some time.
butterfly
Dawes took the longest route
The one that took the longest to build :D
The Cologne Cathedral in Colonge, Germany took 640 years to complete (1248-1880).
Saint Valentine of Rome was never officially canonized. He died many years before the process of canonization existed. He was declared a saint by the early Church based on his life of heroic virtue and martyrdom.
It took about 498 years after her death until she was canonized in 1920 by Pope Benedict XV. The reason it took so long was the fact that few documents could be found upon which to base her sainthood. In the late 19th century documents were found that described her trial and the answers which she gave to her persecutors. Based on this new information Joan was finally given the reward she deserved.
Becoming a saint in the Catholic Church typically involves a lengthy process that can take several decades or even centuries after a person's death. The process includes beatification (when a person is declared "blessed") and canonization (when a person is officially recognized as a saint). The time frame can vary depending on the complexity of the case and the availability of evidence.
Virgin, patroness of America, born at Lima, Peru 20 April, 1586; died there 30 August, 1617. At her confirmation in 1597, she took the name of Rose, because, when an infant, her face had been seen transformed by a mystical rose. As a child she was remarkable for a great reverence, and pronounced love, for all things relating to God. This so took possession of her that thenceforth her life was given up to prayer and mortification. She had an intense devotion to the Infant Jesus and His Blessed Mother, before whose altar she spent hours. She was scrupulously obedient and of untiring industry, making rapid progress by earnest attention to her parents' instruction, to her studies, and to her domestic work, especially with her needle.