Since returning as commissioner of the New York Police Department, William J. Bratton has been generous in thanking those who helped him get here: the mayor, Bill de Blasio, for the job; his wife, Rikki Klieman, for her support; even a children’s book, for igniting his boyhood fascination with the police.

And for just about everything else, Sir Robert Peel.

Throughout the department, the influence of Peel, a 19th-century British prime minister who is considered the father of the London police force, is evident. Either in name or in the nine basic policing principles commonly attributed to him, Peel is everywhere — on Mr. Bratton’s lips, his official department blog, and even next to the place settings of breakfast events where Mr. Bratton is the guest of honor.

In Peel, Mr. Bratton seems to have found a touchstone for nearly every occasion, a visionary who “got it so right so long ago” and whose theory offers a kind of policing originalism that floats above the particularities of each force he has commanded. What was good for London in 1829, Mr. Bratton appears to suggest, remains just as good for officers in modern-day New York.

“I’m privileged to be part of a long line of police leaders beginning with Sir Robert Peel,” Mr. Bratton said in December, minutes after Mr. de Blasio had introduced him as the next police commissioner. Taking out a folded piece of paper, Mr. Bratton began introducing New Yorkers to the nine principles attributed to Peel. “I carry these with me everywhere,” he said. “My bible.”