It was one of the best days of Kate McGovern's life. The 21-year old CaliforniaA large state on the west coast of the USA. It is the country's most populous state, with more than 37 million people. First settled by Native Americans as much as 13,000 years ago, the area was subsequently conquered by Spain, then was absorbed into Mexico, which was forced to hand it over to the USA in 1848. native had wrangled a ticket to the premiere of The Eras Tour - the record-breaking film adaptation of Taylor Swift's current concert tour.¹ McGovern said: "I'm just like, overwhelmed right now... My stomach hurts, but, like, in the best way possible."

SwiftiesFans of singer Taylor Swift. feel on top of the world. Swift herself actually is. She has a run of critically and commercially successful albums. Eras is on course to being the most successful tour ever.² Night after night she has basked in the adoration of tens of thousands of fans. Many of them see her as the greatest artist of all time.

But this status is not unchallenged. Tomorrow, another musical colossus will begin her own worldwide tour at London's O2An entertainment area built within the dome of a building that used to be called the Millennium Dome in Greenwich, south east London.: Madonna, for decades known as the Queen of Pop.

Fans are bitterly divided over who really should hold the title. Swift has more big awards, beating Madonna in both GrammysThe most prestigious award in the US music industry. The trophy is shaped like a gilded gramophone. Last year, Billie Eilish won most of the main awards.³ and VMAsThe MTV Video Music Awards⁴. But Madonna has sold more records.⁵ She has had 13 number one singles in the US, while Swift has earned just nine. But Swift wins on overall Billboard Top 40 hits, with 119 to Madonna's 71.

Yet these comparisons can be misleading. Madonna has been active since 1979, Swift since 2004. One came up from New York nightclubs, the other through country music. And the way people listen to music has changed enormously.

It is more relevant to examine their cultural impact. On this, Madonna has a clear advantage. From the late 1980s to the mid 2000s, all eyes were on her. Her biggest hits define their time, from Holiday to Like A Prayer, Frozen to Hung Up.

Madonna has ceaselessly changed her music and style, often ahead of the times. She raised the music video to an art form. She originated the big budget pop concert tour. She even starred in numerous hit (and several flop) films.

And she is also political. She has spoken out about religious hypocrisySaying something is bad, but also taking part in it yourself. , racism and homophobia. Some even believe that she has helped redefine women's roles in society. According to biographer Mary Gabriel, she created "a new woman, a person who exercised her power freely".

Madonna took risk after risk, sometimes falling into trouble. Swift has been more cautious. It took until 2018 for her to express a political opinion. Her music has tended to stay close to her country pop roots, while Madonna tries out everything from jazz to reggaetonA style of popular electronic music that first emerged in Panama in the 1980s. It is popular across the Spanish-speaking Caribbean. .

Instead of seeking to please everyone with mixed results, Swift has doubled down on pleasing her fans. As pop critic Louis Mandelbaum says: "She is only in communication with the people that love her, and doesn't need to care about the people who don't".

This might be Swift's unique superpower. Many pop stars, Madonna included, depict themselves as untouchable icons. Swift instead promotes her normality. Many Swifties see her as a friend or an older sister, someone to identify with. And this makes her a great artist in a new way.

Yes: Swift writes powerful songs that speak to the heart. But Madonna's decades-long career is full of bold left turns and reinventions. Swift is a star for today. Madonna will be a star forever.

No: From John Donne's poetry to Franz Schubert's songs, great art wears its heart on its sleeve. While Madonna poses and plays dress up, Swift has always expressed her feelings. She is a true artist.

Or... Neither. Madonna and Taylor are queens of pop. But the real empress is Beyonce - while the others have had ups and downs, Beyonce has been on top form for almost 30 years without a single slip-up.