Fulfillment!

To me, one of the coolest things about confirming the discovery of the Higgs boson is that physicist Peter Higgs lived long enough to see it happen. Higgs' mathematical models predicted the particle in 1964 but experimental confirmation awaited the right equipment to conduct those experiments and measure the results.

Alexis Bouvard, for example, calculated the location of the planet Neptune based on irregularities in the orbit of Uranus but did not live to see the planet's existence confirmed in 1846, three years after his death. Percival Lowell followed the same path in the discovery of Pluto; the differences between the predicted orbit of Neptune and the observed orbit led him to conclude another body more distant from the sun was affecting the ice giant. He calculated where it should be and ironically even photographed it more than once during his telescopic search, but Pluto's discovery wasn't confirmed until fourteen years after his death.