At the beginning of the 19th century, the area of modern-day Italy, at the time a collection of various states and kingdoms, was estimated to have a population of nineteen million, a figure which would grow steadily throughout the century, and by the establishment of the Kingdom of Italy in 1861, the population would rise to just over 26 million.

Italy’s population would see its first major disruption during the First World War, as Italy would join the Allied Forces in their fight against Austria-Hungary and Germany. In the First World War, Italy’s population would largely stagnate at 36 million, only climbing again following the end of the war in 1920. While Italy would also play a prominent role in the Second World War, as the National Fascist Party-led country would fight alongside Germany against the Allies, Italian fatalities from the war would not represent a significant percentage of Italy’s population compared to other European countries in the conflict. As a result, Italy would exit the Second World War with a population of just over 45 million.

From this point onwards the Italian economy started to recover from the war, and eventually boomed, leading to increased employment and standards of living, which facilitated steady population growth until the mid-1980s, when falling fertility and birth rates would cause growth to largely cease. From this point onward, the Italian population would remain at just over 57 million, until the 2000s when it began growing again due to an influx of migrants, peaking in 2017 at just over 60 million people. In the late 2010s, however, the Italian population began declining again, as immigration slowed and the economy weakened. As a result, in 2020, Italy is estimated to have fallen to a population of 59 million.

During the Second World War, the three Axis powers of Germany, Italy, and Finland mobilized the largest share of their male population. For the Allies, the Soviet Union mobilized the largest share of men, as well as the largest total army of any country, but it was restricted in its ability to mobilize more due to the impact this would have on its economy. Other notable statistics come from the British Empire, where a larger share of men were drafted from Dominions than from the metropole, and there is also a discrepancy between the share of the black and white populations from South Africa.

However, it should be noted that there were many external factors from the war that influenced these figures. For example, gender ratios among the adult populations of many European countries was already skewed due to previous conflicts of the 20th century (namely WWI and the Russian Revolution), whereas the share of the male population eligible to fight in many Asian and African countries was lower than more demographically developed societies, as high child mortality rates meant that the average age of the population was much lower.

Sikhism is a religion that originated on the Indian subcontinent during the fifteenth century. Sikhs follow the teachings of 'gurus', who descend from the first guru Guru Naruk who established the faith. Followers of Sikhism are monotheists, believing in only one god, and other core beliefs include the need to meditate, the importance of community and communal living, and the need to serve humanity selflessly (or 'seva'). Sikhism and the British Empire In total, there are around 26 million Sikhs worldwide, and over 24 million of these live in India. Outside of India, the largest Sikh populations are mostly found in former territories of the British Empire - the UK and Canada both have Sikh populations of over half a million people. Migration from India to other parts of the British Empire was high in the 19th century, due to the labor demands of relatively newer colonies, as well as those where slavery had been abolished. These countries also remain popular destinations for Sikh migrants today, as many are highly trained and English-speaking. Other regions with significant Sikh populations Italy also has a sizeable Sikh population, as many migrated there after serving there in the British Army during WWI, and they are now heavily represented in Italy's dairy industry. The Sikh population of Saudi Arabia is also reflective of the fact that the largest Indian diaspora in the world can now be found in the Middle East - this is due to the labor demands of the fossil fuel industries and their associated secondary industries, although a large share of Indians in this part of the world are there on a temporary basis.