Here is a wonderful article on the strongest beginning of the abolitionist movement in the UK (1787). It is a testimony for both grassroots movements and perseverance. In the grander scheme of things, 50 years is only a blink of an eye and well worth it.
Its hard to keep fighting when you know you may not see the change you seek in your own lifetime. But we should begin to embrace the ideas of legacy from an activism point of view, rather than something unchangeable handed down through the ages.