Meta CEO Mark Zuckerberg took the stand on Monday in a historic antitrust trial that could force the tech giant to break off Instagram and WhatsApp, startups it bought more than a decade ago that have since grown into social media powerhouses.

In a string of visits, dinners, calls, monetary pledges and social media overtures, big tech chiefs have joined a parade of business and world leaders in trying to improve their standing with President-elect Donald Trump before he takes office in January.