BEIJING — Thousands of Chinese students took to the streets in Beijing 100 years ago Saturday, in a famous uprising against Western colonialism that still resonates today.

The protest became known as the May 4 Movement, a pivotal moment in Chinese history that the national leader, Xi Jinping, this week commemorated by praising patriotism and urging Chinese youth to “obey the party and follow the party.”

Here is why the movement matters, and why both supporters and critics of the Communist Party claim inspiration from it.

[Read about how Mr. Xi hailed the historic revolt but warned students not to get any ideas.]

What happened on May 4, 1919?

China had sided with the Allies in the First World War, and many Chinese expected that negotiators in the postwar peace talks would agree to hand back colonial territory in Shandong, an eastern Chinese province, that Japan had seized from Germany near the start of the war. Instead, the Western powers let Japan keep the territory.