John Unitas went to his grave believing he had bungled his debut with the Baltimore Colts.

He was wrong.

Fifty years ago this month, the Hall of Fame quarterback threw his first pro pass. According to Unitas, the date was Oct. 21, 1956, and the pass was intercepted by the Chicago Bears' J.C. Caroline, who returned it 59 yards for a touchdown.

Unitas told that tale to the day he died four years ago. But a check of the records proved his timetable off.

His premiere actually occurred two games earlier, late in a 31-14 loss to the Detroit Lions. On a foggy Oct. 6, the rookie trotted onto the field before 42,622 at Memorial Stadium to replace a struggling George Shaw.

Unitas started his career with an incomplete pass. Then, from the Colts' 15-yard line, he took off running for a 23-yard gain. On the next play, his pass was picked off by Detroit's Jim David, who returned the ball 5 yards to near midfield. End of game.

Unitas, it seems, could do more than set aerial records. He could rewrite history.

"Everyone - players, reporters, fans - always believed the story he told about his first pass being run back for a touchdown," Tom Callahan said yesterday. Callahan wrote Johnny U, a biography released last month in which he, too, fell prey to Unitas' account.

Yesterday, in a story about that book, The Sun also reported Unitas' debut incorrectly.

Did No. 19 deliberately lead his fans astray? Callahan said the world will never know.

"Unitas had the all-time memory," Callahan said. "How could he forget his first NFL pass? He wouldn't lie to make it a better story. If anything, John would dull things down. What doesn't change is the fact that when he entered that game on Oct. 21, he never gave the job back."

Callahan and several Baltimore Colts alumni are in town for tomorrow's "Remembering Unitas" celebration at Sports Legends at Camden Yards - timed to coincide with Unitas' reckoning of the past.

One of those attending is Raymond Berry. He doesn't believe Unitas bamboozled the public on purpose. "I've lived long enough to know that human memory has pitfalls when you're thinking in terms of 30, 40 or 50 years," the Colts' Hall of Fame receiver said.

"Besides, it's still true that John's first NFL touchdown pass was to J.C. Caroline. He would be happy to know that he got that right."

mike.klingaman@baltsun.com