Chicago Cubs first baseman Anthony Rizzo hits a two-run single against the Los Angeles Dodgers in the 6th inning during game four of the 2016 NLCS playoff baseball series at Dodger Stadium. Gary A. Vasquez/USA Today/Reuters

It all started in 1945 when William Sianis tried to take his goat, Murphy, to a Chicago Cubs game for luck and the goat was denied entry. That’s when Sianis, the proprietor of the venerated Chicago drinking establishment Billy Goat Tavern, cursed the North Siders.

With the Cubs tied with the Los Angeles Dodgers in the National League Championship series 2-2, fans worry the curse may never be lifted.

Before Oct. 6, 1945, the Cubs were among the most successful teams in baseball, with 51 winning seasons to their credit, two World Series wins and 16 pennants.

Sianis, whose nickname was “Billy Goat,” pleaded with Cubs owner P.K. Wrigley to let the goat in to that day’s game. Wrigley refused and when Sianis asked why not, Wrigley responded, “Because the goat stinks.”

“The Cubs ain’t gonna win no more. The Cubs will never win a World Series so long as the goat is not allowed in Wrigley Field,” Sianis is said to have responded.

For the next 25 years the Cubs were in the basement more often than not.

Then came 1969. The Cubs were so close. The team was in first in mid-August. The National League pennant was within reach. Then along came the “Miracle” Mets, who overtook the Cubs and dashed a city’s hope. The Mets’ general manager at the time was named Johnny Murphy.

In 1973, Sianis’ nephew, Sam, who took over the Billy Goat Tavern from his uncle, brought a goat to Wrigley Field in a bid to end the curse. The goat, a descendant of Murphy named Socrates, traveled in style in a white limo, but also was denied entry. The Cubs lead fizzled mid-season.

When the Tribune Co. bought the Cubs, the goat was invited to the opening day in 1984. Sam Sianis led his goat around the field and declared the curse lifted. The Cubs won their first division title in nearly 40 years but failed to capture a World Series berth, falling to the San Diego Padres, at Jack Murphy Stadium.

Sianis tried again to lift the curse in 1989. The Cubs again captured a division title, but lost out to the San Francisco Giants.

The Cubs opened the 1994 season with a humiliating 12-game losing streak. Sianis came to the rescue. He even recruited former Cubs slugger Ernie Banks to bolster the effort. The gesture ended the losing streak but it still was a miserable season.

In 1998, the Cubs managed to defeat the San Francisco Giants for a wild card berth but they left Sianis and his goat behind when they headed for Atlanta and got swept.

The Cubs won their first division title in 14 years in 2003, beating the Atlanta Braves. The Cubs needed just five more outs against the Florida Marlins to win their first trip to the World Series in 71 years. But a fan, Steve Bartman, snatched a foul ball away from left fielder Moises Alou, breaking the Cubs rhythm and sending the series downhill.

Last year, again the Cubs came so close, beating the St. Louis Cardinals to win the division but then losing the National League Championship to the New York Mets.

The Cubs’ two World Series wins came in 1907 and 1908 when the team was owned by Charles Murphy. The last time the Cubs played in a World Series was 1945.

Can the Cubs break the curse this year?