Raúl Castro, 86, has stood down as president of Cuba and has been replaced by Miguel Díaz-Canel, 57, the vice-president which means almost 60 years and 11 US Presidents later, Cuba is about to be governed by someone other than a Castro for the first time since 1959.
Usually you can determine how successful a leader has been by asking the question 'is my country better off at the end of this persons leadership then when they took over' but the sheer length of time between these events makes that poser almost impossible to answer.
Depending on which side of the political fence you sit, you can point at the economic problems of the island, the denial of political diversity, and its dreadful human rights record and justifiably say Castro and his brother has not been a success.
Alternatively you could point to despite its scant resources, Cuba has fashioned education and health care systems that is the the envy of far richer countries. Illiteracy has been eradicated, while life expectancy at birth in Cuba is about the same as in the US, despite health care spending per capita one 20th the size of that of its richer neighbour.
Considering that most of the 11 US Presidents spent time and resources trying to assassinate the Castro's, that they lasted as long as they did is an achievement in itself but history will be left to decide just how good their leadership was.