The election of Donald Trump as the 45th US president in 2016 was a pivotal moment in history for America and for the world. A celebrity rather than a politician, Trump promised to turn politics on its head - and he did. Is he an aberration or does he represent a continuity of forces already in play? Who was he, where did he come from, and what did he do? These are questions future historians will ask as they grapple with the meaning of Trump, the implications of his presidency and his place in history.