True to his word, Deputy Attorney General Rod Rosenstein resigned from government service after the completion of the Mueller probe. His resignation, which he handed to Trump on Monday, takes effect May 11.

His resignation ends an oftentimes turbulent two years as the number two man in the Department of Justice. Rosenstein oversaw the almost two year-long investigation by special counsel Robert Mueller into Russian interference in the 2016 presidential campaign and the alleged collusion by the Trump campaign. The Mueller report was released only two weeks ago but in redacted form.

"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," wrote Rosenstein in his resignation letter.

Rosenstein made no mention of Mueller and his probe in his resignation letter. Instead, Rosenstein wrote of his department's responsibility to avoid political partisanship and his desire for the DOJ to remain independent from the White House.

Deputy Attorney General Rod Rosenstein Gives Statement On Robert Mueller Indictment Of I3 Russian Nationals

He also made no direct reference to the controversies that marked his tumultuous tenure.

"We enforce the law without fear or favor because credible evidence is not partisan, and truth is not determined by opinion polls," wrote Rosenstein. "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."

Attorney General William Barr praised Rosenstein's tenure, noting his 30-year service in various levels of the justice system is "unparalleled."

"Over the course of his distinguished government career, he has navigated many challenging situations with strength, grace, and good humor," said Barr. "Rod has been an invaluable partner to me during my return to the Department, and I have relied heavily on his leadership and judgment over the past several months."

Rosenstein served throughout both President George W. Bush and President Barack Obama's administrations, and held his position for 12 years.

Rosenstein will be succeeded by Jeffrey Rosen, currently the No. 2 official at the Department of Transportation.

This article originally appeared in IBTimes US.