If you are about on Wednesday, you will notice plenty of people wearing ash on their foreheads. It marks the beginning of the season of Lent, one of those times when we see religiosity permeate into secular society.

The extent to which it is celebrated may surprise you, given the continuing decline in church attendance over the last decade. Yet Lent, like Christmas and Easter, remains a fixture in the calendar for many people.

So, what is Lent and why do Christians mark it?

Lent is a period of fasting or denying yourself of certain pleasures. It takes place in that period between Ash Wednesday and Easter, and is also symbolic of the 40 days Jesus spent fasting in the wilderness after his Baptism as recorded in the Gospels.

In essence, the period of fasting is intended to help a person with their relationship with God. By denying yourself some pleasures of the world, the idea is that you will retreat into a more spiritual time by leaning more heavily on God.

There is no Biblical command to fast, and certainly none to explicitly mark a period of Lent, but it has become a Christian tradition. While it is often more associated with the Catholic Church, it is also observed by many Protestants. For some it is good practice as a reminder that, “Man shall not live on bread alone, but on every word that comes from the mouth of God” (Matthew 4:4).

But it’s not just Christians who mark the festival. For many it leads to a common conversation topic every year: “What are you giving up for Lent?” Many people choose to give up some type of ‘unhealthy’ food, like crisps or chocolate. Making a sacrifice by giving up something we enjoy is within the spirit of Lent; others might be motivated by using Lent to help with their diet and shed a few points, on their way to a ‘summer body’.

It may not seem as important as Christmas or Easter, but Lent certainly remains prominent in society – whether motivated by building a better relationship with God, or by something more individualistic. This does raise the question as to why religious holidays are still held as so universally recognised in an increasingly secular world.

Over Christmas there was some controversy over Mo Salah (probably the most famous Muslim sportsman in the world right now) and Amir Khan (Muslim boxer) posting photos on social media of themselves and their families posing in front of a Christmas tree. The two were criticised by some Muslims (though received support from others) for celebrating a distinctly Christian occasion.

It’s an example of a religious festival having a broader cultural reach. Khan is of course British by birth, and Salah lives in the UK with his family. For them, celebrating Christmas was not a religious celebration, but it simply reflected participation in a longstanding feature of western – just as many other non-Christians celebrate each year.

Over the years these occasions have become more secularized. For many there is a greater focus on snow, Santa and themed coffee cups than there is on Jesus’s birth at Christmas. The symbols associated with Easter are on bunnies and eggs rather than the cross. In fact, I hear more and more people argue that the symbols we associate with these holidays are actually pagan in nature with Christmas trees being associated with Saturnalia (a pagan festival) and bunnies and eggs being fertility symbols associated with the Mesopotamian goddess Ishtar.

The lines between the religious and the secular are far more blurry than sharp; holidays and festivals raise plenty of questions for both those of faith and those of none. Western cultural events may have taken on some new elements that have no influence from the Bible, but why do they remain so important to society? Does their celebration involve a broader belief that Christian values are good, useful and a solid foundation on which to base our morals and by extension our laws? Or have their dates simply been converted into a new kind of holiday or celebration because society simply wants some big occasions to celebrate collectively and inclusively?

Those are just some questions for us to reflect upon this Lent.