When was the story element of Bruce Wayne being trained by mentors introduced into the comics? [duplicate]

Question

In the original version of Batman’s origin, after Bruce Wayne promises to avenge the murder of his parents the next panel shows him wearing a lab coat and in the next he’s lifting a dumbbell.

In the modern version of Batman’s origin, after Bruce Wayne promises to avenge the murder of his parents we see how, as a young adult, he traveled the world and was trained by various mentors.

My question is which story introduced the concept of the many mentors who trained a young Bruce Wayne as he traveled the world, who wrote this story and when and in which comic was it first published.

PLEASE NOTE: I AM NOT ASKING WHO WERE THE SIX OR HOWEVER MANY PEOPLE WERE WHO TRAINED BATMAN I'M ASKING AT WHAT POINT IN THE CHARACTER'S PUBLICATION HISTORY WAS THE CONCEPT OF MENTORS WHO TRAINED HIM INTRODUCED!

Answer 1

According to the DC wikia:

Nevertheless, details of Batman's history were altered or expanded upon through the decades. Additions include meetings with a future Superman during his youth, his upbringing by his uncle Philip Wayne (introduced in Batman #208, January/February 1969) after his parents' death, and appearances of his father and himself as prototypical versions of Batman and Robin, respectively. In 1980, then-editor Paul Levitz commissioned the Untold Legend of the Batman limited series to thoroughly chronicle Batman's origin and history.

Untold Legend of the Batman seems to be the first to introduce multiple mentors:

his becoming the first "Robin" and teaming up with detective Harvey Harris; his attending Gotham College, where he learned the difference between law and justice from Prof. Amos Rexford;

The "modern" version of traveling the world seems to have been introduced after the Crisis of Infinite Earths reboot in Frank Miller's Batman: Year One (1987).