Short answers, pulled from the story.
Henry Cavendish wrote an unpublished manuscript suggesting that Newtonian gravity could bend starlight around a massive object in 1784. This work predated Johann Georg von Soldner's published calculations from 1801 which derived the same value.
Albert Einstein became the first person to calculate the accurate amount of light bending required by the full theory in 1915 while completing general relativity. His previous calculation from 1911 using only the equivalence principle was exactly half the correct value found later.
The first actual discovery occurred in 1979 when Dennis Walsh, Bob Carswell, and Ray Weymann used the Kitt Peak National Observatory 2.1 meter telescope. They identified the Twin QSO SBS 0957+561 as one object split by gravity after it initially appeared as two identical quasistellar objects.
Albert Einstein predicted in 1936 that light rays skirting the Sun's edges would converge to a focal point approximately 542 astronomical units from the star. A probe positioned at this distance or beyond could use the Sun as a gravitational lens to magnify distant objects on the opposite side.
Research published the 30th of September 2013 in Physical Review Letters discovered B-modes formed due to gravitational lensing using the South Pole Telescope. This discovery opened possibilities for testing theories about how the universe originated.