The earliest point where scientists can make reasonable estimates for the population of global regions is around 10,000 years before the Common Era (or 12,000 years ago). Estimates suggest that Asia has consistently been the most populated continent, and the least populated continent has generally been Oceania (although it was more heavily populated than areas such as North America in very early years). Population growth was very slow, but an increase can be observed between most of the given time periods. There were, however, dips in population due to pandemics, the most notable of these being the impact of plague in Eurasia in the 14th century, and the impact of European contact with the indigenous populations of the Americas after 1492, where it took almost four centuries for the population of Latin America to return to its pre-1500 level. The world's population first reached one billion people in 1803, which also coincided with a spike in population growth, due to the onset of the demographic transition. This wave of growth first spread across the most industrially developed countries in the 19th century, and the correlation between demographic development and industrial or economic maturity continued until today, with Africa being the final major region to begin its transition in the late-1900s.

Between 1501 and 1866, it is estimated that over 12.5 million people were forced onto ships in Africa, and transported to the Americas as slaves. Furthermore, it is estimated that only 10.7 million of these slaves disembarked on the other side of the Atlantic, meaning that roughly 1.8 million did not survive the journey. The transatlantic slave trade was a part of the triangular trade route between Europe, Africa and the Americas, during the sixteenth and nineteenth centuries. Generally speaking, this route saw European merchants bring manufactured products to Africa to trade for slaves, then transport the slaves to the Americas to harvest raw materials, before taking these materials back to Europe where they would then be consumed or used in manufacturing. Slavery was an integral part in funding the expansion of Europe's colonial empires, which shaped the modern and highly globalized world in which we live today.

The Middle Passage As with trade, the slave journey was also broken into three parts; the First Passage was the stage where slaves were captured and transported to African ports, the Middle Passage was the journey across the Atlantic, while the Final Passage was where the slaves were transported to their place of work. The death toll in the First Passage is thought to be the highest of the three stages, as millions were killed or fatally wounded as they were captured, however a lack of written data and historical evidence has made this number difficult to estimate. In contrast, shipping records from the time give a much more accurate picture of the Middle Passage's death toll, and this data suggest that roughly 14.5 percent of slaves did not survive the journey. The reason for this was the harsh and cramped conditions on board; slave ships were designed in such a way that they could fit the maximum number of slaves on board in order to maximize profits. These conditions then facilitated the spread of diseases, such as smallpox and dysentery, while malnutrition and thirst created further problems. Generally, slavers aimed to keep slaves as healthy (therefore; profitable) as possible, although there are countless examples of mistreatment and punishment of slaves by their captors, and several cases where slaves were exterminated by the crew as provisions ran low.

Rise and fall of the transatlantic slave trade

The European arrival in the Americas also saw the introduction of virgin soil epidemics (new diseases being introduced to biologically defenseless populations) which decimated the indigenous populations. The abundance of natural resources, but lack of available labor led to the rise of the transatlantic slave trade. Until the mid-1600s, Portuguese traders had a near-monopoly on this trade, supplying slaves to the newly expanding Spanish and Portuguese empires in South America. As other European powers began to expand their empires in the Caribbean and North America, the slave trade grew dramatically, and during the eighteenth century, the number of slaves being brought to the New World increased from an annual average of thirty thousand in the 1690s to 87 thousand in the 1790s. The transatlantic slave trade reached its peak between the 1750 and 1850, and an average of 74 thousand slaves were brought to the Americas each year between these dates. The largest decline came as the slave trade was disrupted during the American War of Independence (1775-1783), although the trade became weakened as the abolitionist movement gained momentum in Europe and the Americas around the turn of the century. The most significant impacts came as the slave trade was abolished in Britain and the U.S. in 1807 and Brazil in 1831, and Britain then used its position as the global superpower to impose abolition on other nations and used the Royal Navy to enforce these measures. While most nations abolished the slave trade in the early 1800s, it would take decades before the actual practice of slavery would be abolished; today, slavery is illegal in almost every country, however modern slavery in the forms of forced labor, human trafficking and sexual exploitation continues to be prevalent across the globe.

During the eighteenth century, it is estimated that France's population grew by roughly fifty percent, from 19.7 million in 1700, to 29 million by 1800. In France itself, the 1700s are remembered for the end of King Louis XIV's reign in 1715, the Age of Enlightenment, and the French Revolution. During this century, the scientific and ideological advances made in France and across Europe challenged the leadership structures of the time, and questioned the relationship between monarchial, religious and political institutions and their subjects. France was arguably the most powerful nation in the world in these early years, with the second largest population in Europe (after Russia); however, this century was defined by a number of costly, large-scale conflicts across Europe and in the new North American theater, which saw the loss of most overseas territories (particularly in North America) and almost bankrupted the French crown. A combination of regressive taxation, food shortages and enlightenment ideologies ultimately culminated in the French Revolution in 1789, which brought an end to the Ancien Régime, and set in motion a period of self-actualization.

War and peace

After a volatile and tumultuous decade, in which tens of thousands were executed by the state (most infamously: guillotined), relative stability was restored within France as Napoleon Bonaparte seized power in 1799, and the policies of the revolution became enforced. Beyond France's borders, the country was involved in a series of large scale wars for two almost decades, and the First French Empire eventually covered half of Europe by 1812. In 1815, Napoleon was defeated outright, the empire was dissolved, and the monarchy was restored to France; nonetheless, a large number of revolutionary and Napoleonic reforms remained in effect afterwards, and the ideas had a long-term impact across the globe. France experienced a century of comparative peace in the aftermath of the Napoleonic Wars; there were some notable uprisings and conflicts, and the monarchy was abolished yet again, but nothing on the scale of what had preceded or what was to follow. A new overseas colonial empire was also established in the late 1800s, particularly across Africa and Southeast Asia. Through most of the eighteenth and nineteenth century, France had the second largest population in Europe (after Russia), however political instability and the economic prioritization of Paris meant that the entire country did not urbanize or industrialize at the same rate as the other European powers. Because of this, Germany and Britain entered the twentieth century with larger populations, and other regions, such as Austria or Belgium, had overtaken France in terms of industrialization; the German annexation of Alsace-Lorraine in the Franco-Prussian War was also a major contributor to this.

World Wars and contemporary France

Coming into the 1900s, France had a population of approximately forty million people (officially 38 million* due to to territorial changes), and there was relatively little growth in the first half of the century. France was comparatively unprepared for a large scale war, however it became one of the most active theaters of the First World War when Germany invaded via Belgium in 1914, with the ability to mobilize over eight million men. By the war's end in 1918, France had lost almost 1.4 million in the conflict, and approximately 300,000 in the Spanish Flu pandemic that followed. Germany invaded France again during the Second World War, and occupied the country from 1940, until the Allied counter-invasion liberated the country during the summer of 1944. France lost around 600,000 people in the course of the war, over half of which were civilians. Following the war's end, the country experienced a baby boom, and the population grew by approximately twenty million people in the next fifty years (compared to just one million in the previous fifty years). Since the 1950s, France's economy quickly grew to be one of the strongest in the world, despite losing the vast majority of its overseas colonial empire by the 1970s. A wave of migration, especially from these former colonies, has greatly contributed to the growth and diversity of France's population today, which stands at over 65 million people in 2020.

In 1800, the population of Portugal was estimated to be approximately 2.8 million; a figure that would see gradual growth throughout the 19th century. During this time, Portugal experienced a series of political and military challenges, including an invasion by Napoleonic France, the cessation of Brazil (it's largest colony), and a civil war caused by royal succession; nonetheless, Portugal remained an international power throughout the 1800s, with significant spheres of influence on all continents. 20th century At the turn of the 20th century, Portugal's international standing began to diminish, and its weakening position in Africa initiated a wave of civil unrest in the metropole. In 1908, following a period of political instability, King Carlos I and his heir were assassinated in Lisbon, and the 5 October 1910 Revolution permanently brought an end to the monarchy. This, however, did not end the political instability, which was further exacerbated by the impacts of the First World War and Spanish Flu pandemic (which, combined, resulted in the deaths of more than 220,000 Portuguese people). Portugal would then experience a rapid population gain following the establishment of the Second Republic (Estado Novo) in 1933, under the 34 year reign of António de Oliveira Salazar, which would see Portugal’s currency stabilized and significant economic growth lasting until the 1960s. However, Portugal’s population would decline in the early 1960s, as escalating colonial wars overseas, combined with increasing political instability at home would see many citizens emigrating elsewhere in Europe; particularly youths attempting to avoid the country’s military draft. Growth would largely resume following the end of the dictatorship with the Carnation Revolution of 1974, as many Portuguese migrants in the now independent colonies would return to Europe. Recent decades While growth would slow (and decline slightly) amidst economic troubles in the 1980s, Portugal’s population generally increased until 2008, when it peaked at 10.6 million people. From 2008 until today, a combination of the long term impacts of the 2008 financial crisis and declining fertility rates have resulted in a steady drop in the country’s population. As a result, in 2020, Portugal is estimated to have fallen to 10.2 million people, although it is also regarded as one of the most stable, peaceful and democratic countries in the world.