(CNN) -- It's been 50 years since the Beatles appeared on "The Ed Sullivan Show" on February 9, 1964, the apex of the so-called "British Invasion" of the United States. A few months later, the Fab Four starred in "A Hard Day's Night" -- which film critic Gene Seymour calls "the best summer movie ever made."
Here are five things you need to know about Beatlemania and the significance of the Beatles' performance on Ed Sullivan's show:
1. Who was Ed Sullivan?
Edward Vincent Sullivan was not what you think of as a TV personality. He was a baggy-eyed, malaprop-mouthed, stiff-bodied former newspaper columnist who looked like Richard Nixon. A wall had more charisma.
But he was the perfect host. He said his introductions and got out of the way. His guests were the stars -- and he could book almost everybody, thanks to his deep contacts. You might compare his show to an hour of Web-surfing. It featured everybody from plate-spinners to comedians to theatrical performances to pop stars, all in one place. Animal acts, too.
"The Ed Sullivan Show," originally called "Toast of the Town," went on the air in 1948 and lasted for 23 years.
2. Were The Beatles really unknown in America?
Not completely. In Britain, they'd had No. 1 singles for several months, starting with "Please Please Me" in February 1963, and by fall Beatlemania was in full swing. (The word "Beatlemania" first gained wide currency in October after the band's performance on a major UK TV show, "Sunday Night at the London Palladium.")
Sullivan first encountered the band by accident -- he was stuck at London's Heathrow Airport when they returned from Sweden to thousands of fans on October 31 -- but the group was on the show's radar before then, Sullivan staffer Vince Calandra says. The show put out a press release about The Beatles' three-show booking in mid-December, and The New Yorker ran a small item in its December 28, 1963, issue. The Beatles had also appeared in several U.S. news reports.
In December, the band's U.S. label, Capitol Records, started a marketing blitz -- "The Beatles Are Coming!" -- and by January their songs were all over the radio. "I Want to Hold Your Hand" hit No. 1 in the United States on February 1, dethroning balladeer Bobby Vinton's "There! I've Said It Again."
But for all that, The Beatles hadn't performed in America. With the Sullivan show, they had one of the biggest stages in the country.
3. Who was there?
CBS received 50,000 requests for the 728 seats in New York's CBS Studio 50, since renamed the Ed Sullivan Theater and now home to "The Late Show with David Letterman." Among the celebrities who attended either the live show or the dress rehearsal: Kathy and Nancy Cronkite (Walter's daughters) Randy Paar (talk-show host Jack's daughter) and Julie and Tricia Nixon (Richard's daughters, invited by Randy Paar). Also there: future Monkee Davy Jones, who performed with the cast of "Oliver!"
4. Wait. It wasn't just The Beatles?
No. The band played two sets, opening the show with "All My Loving," "Till There Was You" and "She Loves You" and returning with "I Saw Her Standing There" and "I Want to Hold Your Hand." In between, acts included magician Fred Kaps, impressionist (and future "Batman" Riddler) Frank Gorshin, comedians Charlie Brill & Mitzi McCall, Welsh singer Tessie O'Shea, Broadway star Georgia Brown and the "Oliver!" cast, and acrobats Wells & the Four Fays.
5. What happened after the show?
Though the audience loved them and millions of new fans were created that night, some reviewers were less enthusiastic. "The cynical turnover in teen-age trauma received recognition last night in the businesslike appearance of The Beatles on the 'Ed Sullivan Show,' " wrote the unimpressed New York Times TV critic Jack Gould. The ratings, however, were spectactular: 45.3% of U.S. TV households tuned in, representing 73 million people -- a record for an entertainment program up to that time.
From New York, The Beatles took a train to the nation's capital, where they played at the Washington Coliseum on February 11, then returned to New York for two Carnegie Hall concerts on February 12. Then it was off to Florida for the group's second Sullivan appearance -- a performance at Miami Beach's Deauville Hotel on February 16. The ratings for the second Sullivan show were almost as good as the first.
On February 22, The Beatles returned to Britain, where they were greeted by 10,000 fans at Heathrow Airport. The third Sullivan appearance, taped before the February 9 show, aired the next day.