The 85-year-old has steered Cuba through stormy waters since taking over from Fidel, but his death and Trumps presidency will test him as never before
Ral Castro has spent most of his life in his brothers shadow, but he has proved a more than capable successor as Cuban president.
A cautious pragmatist to Fidels charismatic ideologue, many felt the younger sibling was a mere stopgap when he formally assumed power in 2008.
But he has subsequently made his own very distinctive mark on the islands history with a program of economic reforms, an easing of travel restrictions and the restoration of diplomatic relations with the United States.
The death of Fidel and the looming presidency of Donald Trump, whose Cuban policy remains unclear, are uncharted waters which will test Rals nerve and judgment as never before.