HONG KONG — Malaysia’s king resigned on Sunday, becoming the first monarch to abdicate in the country’s history.

The royal palace offered no explanation for why the king, Sultan Muhammad V of Kelantan, stepped down after serving only two years of a five-year term. It has also declined to comment on a widespread rumor that his departure was tied to his marriage to a former beauty queen in Russia during a recent medical leave.

But this much is clear: A king’s role in Malaysia has little parallel among the world’s monarchies.

What explains the king’s term limit?

The monarch’s position, officially the “yang di-pertuan agong,” rotates every five years among a group of hereditary sultans who are titular leaders of nine Malay states. (The other four states have governors instead.)

The power-sharing arrangement was developed when Malaysia became independent from Britain in 1957 and the sultans — who had previously ruled independently, with support from the British colonial authorities — needed to nominate a figurehead to rule over a newly federalized nation.