After more than two decades, Yahoo's time as an independent company has finally come to an end.

Verizon (VZ) officially completed its deal to acquire Yahoo's (YHOO) core Internet assets for $4.48 billion after months of uncertainty about the deal, both companies announced Tuesday.

Yahoo CEO Marissa Mayer is resigning from the company. She will receive a $23 million severance package, according to an earlier company filing.

"Given the inherent changes to my role, I'll be leaving the company," Mayer wrote in an email to the company. "However, I want all of you to know that I'm brimming with nostalgia, gratitude and optimism."

"Verizon wishes Mayer well in her future endeavors," the company said in a statement.

Yahoo and AOL will form a new digital media company under Verizon called Oath. Verizon's goal is to use Yahoo's enormous reach to compete with the likes of Facebook (FB) and Google (GOOGL) for online advertising.

Verizon expects to cut as many as 2,100 employees from the combined venture, or about 15% of the staff, according to a source familiar with the matter.

What remains of Yahoo will be renamed Altaba Inc. It will effectively serve as a holding company for Yahoo's large stake in Alibaba (BABA), the Chinese e-commerce company.

The deal's close comes nearly a year after the acquisition was first announced. The acquisition was thrown into doubt after Yahoo disclosed two massive security breaches affecting more than one billion users.

Verizon eventually agreed to move forward after cutting the price tag by $350 million and requiring Yahoo to split the cost of any legal liabilities resulting from the breaches.

Related: Why Marissa Mayer couldn't save Yahoo

The acquisition marks the end of an era for an Internet icon.

Yahoo originally offered a directory of websites to guide users through the new world of the Internet. It was almost synonymous with the Internet itself for much of the 1990s with a market value that topped $100 billion around the dot-com boom.

For the majority of its existence, however, Yahoo struggled to find relevance. It shuffled through CEOs, struggled with whether to be a media or technology company, and bet big on acquisitions like Geocities while passing up a chance to buy Facebook.

Under Mayer, Yahoo made one last push to prove it could be more than a fading Internet pioneer.

Mayer acquired dozens of startups for talent to compete with mobile apps. She also hired big name media personalities like Katie Couric and acquired Tumblr to reach a younger demographic. But these costly efforts did little to turnaround Yahoo's business.

"I'm really sad to see the end of Yahoo as an independent company," says Tapan Bhat, a former senior vice president at Yahoo. "The turmoil of the last few years has obscured the value that Yahoo provided from the earliest days of the web to the latter part of the first decade of the '00s."

While Yahoo's heyday is over, insiders take solace knowing Yahoo alumni remain a force in defining the Internet. Former Yahoos, as they like to call themselves, have founded or run a long list of businesses, including Slack, WhatsApp and LinkedIn.

"They're all around us, in Silicon Valley, and around the globe," says Dan Rosensweig, chairman and CEO of Chegg, and a former COO at Yahoo. "They're continuing to create, define and build upon the digital lifestyle that Yahoo! was once synonymous with."