FBI Director James Comey’s announcement two days ago that he would not to recommend charges against Hillary Clinton following an investigation into her use of a personal email system earned him an invite to Capitol Hill on Thursday, where he testified for nearly five hours before the Republican-led House Oversight Committee.

The decision by Comey and, a day later, the Justice Department, not to pursue a criminal case against the presumptive Democratic nominee has thrust the career prosecutor into the bubbling cauldron of the 2016 presidential contest. But this isn’t the FBI chief’s first time in the headlines.

Here are seven things to know about Comey:

He opposed Bush White House officials in a dramatic standoff

Comey came into national prominence in 2007 when, during testimony to the Senate Judiciary Committee, he told the story of a tense standoff over a federal domestic surveillance program with top officials from the administration of President George W. Bush.

The incident took place in the evening of March 10, 2004, according to Comey’s account, with then-Attorney General John Ashcroft ill and incapacitated in a hospital intensive care unit.

Top White House lawyer Alberto Gonzales (who would later become U.S. attorney general) and Bush Chief of Staff Andrew Card had raced to Ashcroft’s side in an effort to have him sign off on an extension to the wiretapping program, which Justice Department attorneys had deemed illegal. The weakened Ashcroft managed to make clear his refusal and Gonzales and Card left the room — with Comey, then Ashcroft’s top deputy, watching on — without a word.

He prosecuted Martha Stewart