The reason why the Olympics are beginning two days before the opening ceremony

Some athletes will be going home before the games officially start

Since 1896 a delegate, often head of state, has declared the Olympic games open to signal its official start.

At London 2012 the late Queen Elisabeth II said: "I declare open the Games of London, celebrating the XXX Olympiad of the modern era."

In two days time in Paris, French President Emmanuel Macron is expected to do the same, despite the fact that some Olympic events are set to begin today.

It comes as no surprise then that one of the four sports to begin early is also one of the most contentious Olympic events, football, which is to begin outside of the regular Olympic schedule.

The billing for today's matches include Argentina against Morocco and France versus the USA.

The three other sports to begin early include rugby sevens, handball and archery while shooting takes place before the opening ceremony but on the same day (26 July).

In fact in a cruel twist of fate some athletes will be out of the Olympics before it even officially starts due to ranking places for 12th-9th in the rugby sevens being decided tomorrow.

Football starting early at the Olympics is practically tradition now since the same early scheduling has happened since Barcelona 1992 to allow plenty of rest time between matches.

Notably this is a practice FIFA could learn from as they find themselves in a legal battle with football leagues around Europe.

However, for the other sports starting early the reason is not one of rest but rather venue space and availability.

Women's handball will see six preliminary round games played on Thursday at South Paris Arena 6, which are taking place a day earlier to allow the venue to transition into a weightlifting arena.

Meanwhile there will be 24 rugby sevens matches played on Wednesday and Thursday at the Stade de France which must be completed before the athletics takes centre stage in the arena on 1 August.

Archery will also start early at Les Invalides in the centre of Paris on Thursday, with the rankings for the men and women taking place.