Most people don't realise what an incredibly versatile artist Picasso was.
Critics divide Picasso's work into Blue, Pink, Primitive phases, which map major changes in his personal life.
The Blue phase corresponds to his life in Paris in the 1900s, when he was extremely poor, struggled to get commissions, struggled to get food. He burned artworks to heat his atelier. His best friend and fellow artist Casagemas committed suicide.
His work from that period is extremely gloomy and features many outcast figures like beggars, prostitutes and alcoholics.
However as Picasso's personal circumstances changed, so did his style.
He started adding more colours. His tone became more upbeat and optimistic. He experimented with Cubism.
However like many other artists, Picasso was traumatised by the experience of the First World War.
The carnage put a halt to a lot of artistic innovation.
Many artists returned to the reassurance of past artistic traditions.
Arlequin is symptomatic of this period.