Deputy Attorney General Rod Rosenstein submitted his resignation to President Trump on Monday, effective May 11.

The move brought Rosenstein’s often tumultuous two-year tenure to an end, during which he oversaw special counsel Robert Mueller’s sweeping investigation into Russian interference in the 2016 election and was present at key moments during the firing of FBI director James Comey.

While often the subject of the President’s ire — he even privately discussed resigning last year after reports emerged that he had floated wearing a wire to surveil the president — Rosenstein had nothing but praise for his boss in his letter on Tuesday.

“I am grateful to you for the opportunity to serve; for the courtesy and humor you often display in our personal conversations; and for the goals you set in your inaugural address: patriotism, unity, safety, education and prosperity,” he said.

In his resignation letter, Rosenstein praised the Justice Department’s efforts under the Trump administration, while vaguely alluding to some of the more controversial issues of his tenure as the Department’s No. 2 — from the Russia investigation to the attacks on the Justice Department for pursuing the probe.

“Our nation is safer, our elections are more secure, and our citizens are better informed about covert foreign influence efforts and schemes to commit fraud, steal intellectual property, and launch cyberattacks,” Rosenstein wrote in the letter. “We also pursued illegal leaks, investigated credible allegations of employee misconduct, and accommodated congressional oversight without compromising law enforcement interests.”

Rosenstein found himself the target of criticisms from lawmakers on both sides of the aisle at various points in the administration.

Democrats were aghast at the role he played in the termination of Comey — writing a memo criticizing the FBI director’s handling of the Hillary Clinton email probe — that the administration used as cover to explains Trump’s decision.

However, he also appointed the special counsel, and quickly became a foil for Republicans, including for Trump himself, as they sought to smear the Department over the coarse of the investigation. Trump once mocked him for being “from Baltimore” where there “very few Republicans in Baltimore, if any.”

Rosenstein is in fact a Republican, despite staying in his role as U.S. Attorney of Maryland during the Obama administration. He lives in a suburb just outside of D.C.

In Monday’s letter, which came on the heels of an event last week where the outgoing official took a combative tone with the press, Rosenstein fashioned the Department above the fray that was a constant for most of the time he spent leading it.

“We enforce the law without fear or favor because credible evidence is not partisan, and truth is not determined by opinion polls,” Rosenstein said. “We ignore fleeting distractions and focus our attention on the things that matter, because a republic that endures is not governed by the news cycle.”

The letter closed with a reference to President Trump’s campaign slogan.

“We keep the faith, follow the rules, and we always put America first.”

Read Rosenstein’s resignation letter here: