Roy Taylor knows his Bears.

The 39-year-old Yorkville resident has collected hundreds of tapes and highlight reels of Bears games, documented accounts of every Bears season since he started going to games at age 8, and created a website dedicated to Bears history that started as a class project at Illinois Institute of Technology in Wheaton in 2000.

Bearshistory.com and the associated chicagobearsweblog.com have received as many as 10,000 hits per day, Taylor said.

He's also author of Chicago Bears History, a 128-page book published in 2004. One major theme about the Bears and Packers has emerged from his research: "When the Bears have been good, the Packers have been bad. When the Packers have been good, the Bears have been bad," Taylor said. "It's always been that way."

As long as he's been alive, the Bears and their bitter rival have been in the playoffs at the same time only twice: this season, and in 2001.

That's what makes Sunday's NFC Championship game so rare and unique, he said. The two rivals, who have played each other since 1921, have been consistently inconsistent.

The Packers won NFL championships in 1929, 1930 and 1931, and the Bears won the next two. The Packers became good again in the late 1930s until the Bears “had their most famous dynasty,” according to Taylor, in which they won titles in 1940, 1941 and 1943 and earned the moniker "Monsters of the Midway."

The only time the two teams faced each other in the postseason, the Bears won.

On Dec. 14, 1941, the Bears played the Packers on a 16-degree day at Wrigley Field, and notched a 33-17 victory. They then moved on to the NFL Championship where they defeated the New York Giants.

The Bears captured the NFL Championship in 1963, but under coach Vince Lombardi, Green Bay was the team of the ‘60s, winning five championships.

But in most recent history, the memories of Brett Favre's dominance over the Bears are too hard to erase for many Bears fans.

Taylor calls it the Bears' "darkest era." With Favre at quarterback, the Packers beat the Bears 18 out of 22 times.

It's because Taylor remembers those dark days all too well that he never considered selling his two tickets to Sunday's game, even though he says he could probably quadruple his money. At 2 p.m., he'll be in his north end zone seats, surrounded by some 61,499 other fans in what many call the biggest game of the 90-year-old rivalry.

"How many years have we watched terrible Bears teams?" Taylor said. "(It's) probably the only time in a lifetime to see the Bears and Packers in an NFC Championship."