Alibaba Group founder Jack Ma officially retired from his role as chairman Tuesday, marking the end of an era for the world’s largest e-commerce firm.

In a move first announced last year, Ma is handing over the reins to current CEO Daniel Zhang, who now faces the difficult task of steering Asia’s most valuable listed firm at a time when growth in its core e-commerce sector has slowed significantly, China’s economy is faltering and trade tensions are on the rise.

Ma, one of China’s richest and most recognizable businessmen, started the company with a group of friends out of his Hangzhou apartment back in 1999, struggling for years before eventually going on to spark the country’s e-commerce boom. It is now a $460 billion behemoth, with most of its income coming from within mainland China.

Ma is stepping down on his 55th birthday, which coincides with Alibaba’s 20th anniversary. The day was marked by a company celebration at an 80,000-seat, Olympic-sized sports stadium in Hangzhou, an event eyed closely by analysts for indications of Alibaba’s future prospects.

Zhang is an accountant by training and more reserved than the more charismatic Ma, who was prone to making headlines for stunts like dancing to Michael Jackson’s “Billie Jean” in a dazzling outfit at a past anniversary party.

Ma’s retirement announcement raised eyebrows at the time, as it’s unusual for top Chinese executives to step down at such an early age. The former English teacher has said he now plans to turn more towards philanthropy, with a focus on education.

In some ways, the transition is symbolic, as Ma will not totally vanish from the scene. He still holds a 6.22% share and will stay on the board of directors until next year’s annual shareholders’ meeting. After that, he will remain a member of the 38-person Alibaba Partnership, a group with the power to nominate or appoint board members.

When it comes to entertainment, Alibaba’s biggest footprints lie in Tao Piaopiao, one of China’s top online film ticketing platforms; the streaming platform Youku Tudou; performance ticketing platform Damai; and its film production and investment arm, Alibaba Pictures, launched by Ma in 2014.

He was personally instrumental in a 2016 co-production and financing deal with  Steven Spielberg’s Amblin Partners, which has led to joint ventures such as “A Dog’s Journey,” starring Dennis Quaid.

Alibaba Pictures is still majority-controlled by its parent group despite its own listings in Hong Kong and Singapore. It has backed a number of Hollywood titles, including the two most recent “Mission: Impossible” films, “UglyDolls,” and the Oscar-winning “Green Book,” among others.

Ma said he’d watched that last film three times, and told an audience at a Beijing pre-screening: “Alibaba Pictures will introduce more movies like this into China, and we will learn from them and gradually produce movies like this.”

Alibaba’s stock price has risen about 10% in the past year, and revenue in the last quarter was up 42% year-on-year to about $16 billion (RMB115 billion).