Former U.S. President Bill Clinton speaks at a memorial service for the late boxer Muhammad Ali in Louisville, Kentucky on June 10. Reuters

It's not often — or ever — that one of the two major candidates in a general election is the wife of a former president. But then again, nothing about 2016 is normal.

Bill Clinton, who served as president from 1993 to 2001, was scheduled to speak Tuesday night at the Democratic National Convention in support of his spouse, Hillary, the presumptive nominee. His speech is sure to be widely watched, as he was recently ranked the eighth best president in history.

Bill Clinton may be popular now, but he went through a rocky time in the White House in the late '90s — he was even impeached. If you're too young to remember the scandal, have forgotten the details or just want to learn more, read on.

Can you summarize what happened? It all started in 1995, when 21-year-old Monica Lewinsky landed an internship in the chief of staff's office. She and Clinton became involved within months, kissing and eventually having oral and phone sex. She later got a paid position within the federal government, and over the next two years, they had several intimate encounters, according to the Washington Post. Their relationship ended in 1997 as a separate sexual harassment case, filed by a former Clinton worker named Paula Jones, got underway.

During that investigation, Lewinsky was subpoenaed. She denied having an affair with Clinton, but one of her coworkers — a woman named Linda Tripp — secretly recorded Lewinsky's comments about the president. The news broke in 1998, and Clinton rejected the allegations with the now-famous line, "I did not have sexual relations with that woman," according to the History Channel. He was later investigated by a grand jury and admitted he had "inappropriate intimate contact" with Lewinsky.

President Bill Clinton | InsideGov

So he was impeached? Investigator Kenneth Starr submitted a report to Congress on Sept. 9, 1998, including 11 causes for impeaching Clinton, among them perjury and abuse of power, CNN reported. It claimed Clinton's choices were "inconsistent with the president's constitutional duty to faithfully execute the laws."

On Dec. 20, 1998, the House of Representatives impeached Clinton on two of Starr's 11 charges.

Does that mean he left office? Nope. In order for a president to be removed from office, two-thirds of the Senate has to agree. Clinton was tried in the Senate in January 1999 after the House's decision, but there wasn't enough support to convict him. Clinton was acquitted, and he apologized. He finished his term as president in January 2001.

How did Hillary Clinton react to all of this? Business Insider reported the first lady, in private, ate cake and had her husband sleep on the couch while the scandal was unfolding. In public, she stood by Bill Clinton.

"Forgiveness is a choice. And I fully respect those who don’t make that choice, for whatever reason, in their personal or their professional lives but for me it was absolutely the right choice," Hillary Clinton told BBC in 2014, according to the Huffington Post. "For me, it is something that is incredibly difficult but I am grateful every day that that’s the choice that I made and I’ve counseled others to see if in their own hearts they can also do that."

Is it a factor in this election? Yes — Republican nominee Donald Trump has already brought up the litany of accusations against Bill Clinton. "There certainly were a lot of abuse of women, you look at whether it's Monica Lewinsky or Paula Jones, or any of them, and that certainly will be fair game," Trump told MSNBC in December.

He also released a campaign ad on Instagram showing pictures of Lewinsky.

What's Lewinsky doing now? She's an activist against bullying — and she's trying not to get involved in the mudslinging. This past April, a reporter for the Guardian asked whether Lewinsky was concerned Trump would bring her into the election.

"I’m not going to answer that,” she said at the time. “How’s this? I’m affected by what happens on the world stage. But I don’t let it deter me. I’m incredibly grateful for the movement I have in my life right now."