By Stacey Leasca

In April, when Barbara Bush died at the age of 92, the country collectively came together to grieve the loss of one of the most popular first ladies in history. But, perhaps no one mourned the loss more than those closest to her, including her personal secret service agents who stood by her side for years.

Following her death, several agents shared stories of the former first lady's incredible kindness and generosity. But, most telling of all, they also shared her endearing and rather meaningful secret service code name.

"As a special agent with the United States Secret Service, I had the opportunity to work on many protective assignments with Mrs. Bush," Jonathan Wackrow, a former secret service agent, shared with CNN. Wackrow went on to share a personal story about his time protecting the Bushes at their summer home in Kennebunkport, Maine. There, he happened to run into the first lady on the grounds of the home in the early morning hours. She simply looked at Wackrow and said, "Well, it is good morning for me, but it looks like you have been up all night, so I will wish you a good night's sleep."

According to Wackrow, "She was the first Secret Service protectee I had ever spoken to. That encounter is only one of scores of examples my fellow agents could give of the genuine admiration and respect Barbara Bush showed to the people who protected her and her family — and her recognition of the sacrifices the agents made for the presidential security operation."

In a second personal anecdote, Wackrow shared a story of their time together in her post-White House life. At the time, he was escorting her in a motorcade through New York City, which also came with police cruisers, blaring sirens and whole lot of attention.

"Typically, this was not the way that the former first lady liked to travel, as it drew undue attention," he wrote. "However, in this instance – with her husband's presidency behind her -- she was thrilled."

He explained, she took a quick glance in the rear-view mirror of the car, smiled and turned to the staff and said, "They remember me! We have not had this much excitement since the White House!"

So really, reading these stories and more, it's no surprise then that the Secret Service gave her the code name "Tranquility."

"It exemplified her demeanor and its calming, humanizing and gentle effect on those around her," Wackrow wrote. "She will be forever missed."