‘A glimpse of heaven.’ Why the fire at Notre Dame felt so personal to me — and the world.

It has been 67 years since I first set foot on the grounds of Paris’s Notre-Dame cathedral, the medieval architectural marvel that went up in flames this Monday. Pictures in our family photo album show me on the swings in the little playground behind the church. A few years later, I climbed the cathedral’s tower with my father and came face to face with the fantastic gargoyles sticking out high above the city. In my childhood memories, Notre-Dame was a sooty black; I remember my surprise when I came back to Paris after college and discovered that it was now a sandy beige, thanks to a cleaning campaign in the 1960s.

For nearly 70 years, as I have returned to Paris pursuing my career as a professor of French history, the great church has been part of my life. As an undergraduate student, I learned how Gothic pointed arches, borrowed from Islamic architecture, allowed its builders to make a church that soared to the sky and was filled with radiant light. Later, tour guides showed me how the stained-glass windows and sculptures made the cathedral a representation of the “heavenly Jerusalem” for medieval worshippers. Images of the Hebrew prophets paired with Christian saints illustrated the connection between the two faiths, even though statues on the church’s front portal contrasted a blindfolded “Synagogue,” unwilling to accept Jesus, with a radiant “Church” looking up to the sky.

My studies taught me about Notre-Dame’s long history and its multiple meanings. Dedicated to “Our Lady,” the Virgin Mary, the cathedral reflects medieval Christianity’s attitude toward women, temptations to sin but also, through Mary, the means by which, in the Church’s teaching, God became flesh. To the militant Protestants of the Reformation, Notre-Dame was a temple of idolatry which they tried to purify by destroying its images of saints. During the French Revolution, the statues of kings on its facades lost their heads, just like Louis XVI, and Jacobin radicals used what they called a “monument to superstition” as the setting for a “Festival of Reason.” In the nineteenth century, romantic enthusiasts “improved” the cathedral, adding features like the iron steeple that crashed through the roof during this week’s fire.

Over the years, I had many unforgettable experiences at Notre-Dame. I remember joining a crowd of more than 20,000 at midnight mass and listening to the cathedral’s mighty organ straining to be heard over the din. On walks through the city, I often stopped in for a few minutes to admire the stained-glass windows lit up by the afternoon sun. When I was old enough to take my own children to Paris, I tried to interest them in the lively depiction of sinners being thrust down into Hell over the main door. A few years ago, I heard a magnificent performance of Mozart’s “Requiem” and marveled that human voices could fill such an enormous structure. Too often, however, during my various stays in Paris, I fell into the habit of taking Notre-Dame for granted. Glimpsed from the glassed-in terrace of the modernist Centre Pompidou art museum or the balcony of Sacre-Coeur in Montmartre, it was always there, easy to recognize but not particularly calling out to be visited again. Many times, I hurried past the crowds lined up at the entrance, not without a certain snobbish sense of superiority to tourists for whom Notre-Dame was not an old friend.

France’s national cathedral will be restored, but years, indeed decades of painstaking work lie ahead before visitors will again be able to catch a glimpse of heaven inside its walls. Only now, as I contemplate the many ways in which Notre-Dame has been a part of my life, how many different experiences I have had there, and how much I learned from my visits—about art and architecture, about the human ingenuity that went into the cathedral’s construction, about the human thirst for spiritual experience, about the history that unfolded within it—do I begin to grasp what this terrible loss means. Multiply my sense of loss with that of the millions of other people around the world who have visited Notre-Dame, studied it, or simply dreamed of some day seeing it for themselves, and you have a sense of what the world has lost because of this tragic fire.

Jeremy D. Popkin is the William T. Bryan Chair of History at the University of Kentucky. He first visited Notre-Dame cathedral in 1952.