Humanitarian aid
His graphic account of the immense suffering he witnessed, written in his book A Memory of Solferino, became a foundational text to modern humanitarianism.

A Memory of Solferino changed the world in a way that no one, let alone Dunant, could have foreseen nor truly appreciated at the time. To start, Dunant was able to profoundly stir the emotions of his readers by bringing the battle and suffering into their homes, equipping them to understand the current barbaric state of war and treatment of soldiers after they were injured or killed; in of themselves these accounts altered the course of history. Beyond this, in his two-week experience attending to the wounded soldiers of all nationalities, Dunant inadvertently established the vital conceptual pillars of what would later become the International Committee of the Red Cross and International Humanitarian Law: impartiality and neutrality. Dunant took these ideas and came up with two more ingenious concepts that would profoundly alter the practice of war; first Dunant envisioned a creation of permanent volunteer relief societies, much like the ad hoc relief group he coordinated in Solferino, to assist wounded soldiers; next Dunant began an effort to call for the adoption of a treaty which would guarantee the protection of wounded soldiers and any who attempted to come to their aid.
After publishing his foundational text in 1862, progress came quickly for Dunant and his efforts to create a permanent relief society and International Humanitarian Law. The embryonic formation of the International Committee of the Red Cross had begun to take shape in 1863 when the private Geneva Society of Public Welfare created a permanent sub-committee called "The International Committee for Aid to Wounded in Situations of War". Composed of five Geneva citizens, this committee endorsed Dunant's vision to legally neutralize medical personnel responding to wounded soldiers. The constitutive conference of this committee in October 1863 created the statutory foundation of the International Committee of the Red Cross in their resolutions regarding national societies, caring for the wounded, their symbol, and most importantly the indispensable neutrality of ambulances, hospitals, medical personnel and the wounded themselves. Beyond this, in order to solidify humanitarian practice, the Geneva Society of Public Welfare hosted a convention between 8 and 22 August 1864 at the Geneva Town Hall with 16 diverse States present, including many governments of Europe, the Ottoman Empire, the United States of America (USA), Brazil and Mexico. This diplomatic conference was exceptional, not due to the number or status of its attendees but rather because of its very raison d'être. Unlike many diplomatic conferences before it, this conference's purpose was not to reach a settlement after a conflict nor to mediate between opposing interests; indeed this conference was to lay down rules for the future of conflict with aims to protect medical services and those wounded in battle.

The first of the renowned Geneva Conventions was signed on 22 August 1864; never before in history has a treaty so greatly impacted how warring parties engage with one another. The basic tenents of the convention outlined the neutrality of medical services, including hospitals, ambulances, and related personnel, the requirement to care for and protect the sick and wounded during the conflict and something of particular symbolic importance to the International Committee of the Red Cross: the Red Cross emblem. For the first time in contemporary history, it was acknowledged by a representative selection of states that war had limits. The significance only grew with time in the revision and adaptation of the Geneva Convention in 1906, 1929 and 1949; additionally, supplementary treaties granted protection to hospital ships, prisoners of war and most importantly to civilians in wartime.
The International Committee of the Red Cross exists to this day as the guardian of International Humanitarian Law and as one of the largest providers of humanitarian aid in the world.

Late 19th century: Internationally organized humanitarian aid efforts continued to be launched for the rest of the century, often with ever-greater logistical acumen and experience. In 1876, after a drought led to cascading crop failures across Northern China, a famine broke out that lasted several years—during its course as many as 10 million people may have died from hunger and disease. British missionary Timothy Richard first called international attention to the famine in Shandong in the summer of 1876 and appealed to the foreign community in Shanghai for money to help the victims. The Shandong Famine Relief Committee was soon established, with those participating including diplomats, businessmen, as well as Christian missionaries, Catholic and Protestant alike. An international network was set up to solicit donations, ultimately bringing in 204,000 silver taels, the equivalent of $7–10 million if valued at 2012 silver prices.
Simultaneously in India, another campaign was launched in response to the Great Famine of 1876–78. Retrospectively, authorities from across the administrative and colonial structures of the British Raj and princely states have been to various degrees blamed for the shocking severity of the famine, with critiques revolving around their laissez-faire attitude and the resulting lack of any adequate policy to address the mass death and suffering across the subcontinent, though meaningful relief measures began to be introduced towards the famine's end. Privately, a famine relief fund was set up in the United Kingdom, raising £426,000 within its first few months of operation.

Early 20th century: Intertwined with and informed efforts related to the profound destruction and disruption caused by World War I, including that of the Red Cross and Red Crescent organization, the Russian famine of 1921–1922, taking place in a country already immensely burdened with systemic agriculture and logistical struggles—then ravaged by successive periods of industrial war, blockade, bad harvests, the Russian Revolution, its resulting political restructuring and social upheaval, and then the insurgency and war communism of the Russian Civil War that followed. In the nascent Russian Soviet Federative Socialist Republic, Vladimir Lenin allowed his personal friend and acclaimed thinker Maxim Gorky to pen an open letter to the international community asking for relief for the Russian people. Despite the ongoing ideological, material, and military conflicts levied by both the new socialist state and the capitalist international community towards one another, efforts to aid the starving population of Soviet Russia were intensive, deliberate, and effective. American efforts, led in large part future president Herbert Hoover, as well as those by the International Committee for Russian Relief joined extant humanitarian organizations in delivering food and medicine to Russia over the course of 1921 and 1922, at some points feeding over 10 millions Russians every day. With the United States left relatively untouched by World War I, its intensive private and public efforts in Russia constituted a clear expression of its new paramount soft power on the international stage, with power projection from European states having been either totally destroyed or severely limited in scope in the years following the conflict.

1980s: Early attempts were in private hands and were limited in their financial and organizational capabilities. It was only in the 1980s, that global news coverage and celebrity endorsement were mobilized to galvanize large-scale government-led famine (and other forms of) relief in response to disasters around the world. The 1983–85 famine in Ethiopia caused upwards of 1 million deaths and was documented by a BBC news crew, with Michael Buerk describing "a biblical famine in the 20th Century" and "the closest thing to hell on Earth".
Live Aid, a 1985 fund-raising effort headed by Bob Geldof induced millions of people in the West to donate money and to urge their governments to participate in the relief effort in Ethiopia. Some of the proceeds also went to the famine hit areas of Eritrea.

2000s: A 2004 reform initiative by Jan Egeland, resulted in the creation of the Humanitarian Cluster System, designed to improve coordination between humanitarian agencies working on the same issues.

2010s: 

World Humanitarian Summit: The first global summit on humanitarian diplomacy was held in 2016 in Istanbul, Turkey. An initiative of United Nations Secretary-General Ban Ki-moon, the World Humanitarian Summit included participants from governments, civil society organizations, private organizations, and groups affected by humanitarian need. Issues that were discussed included: preventing and ending conflict, managing crises, and aid financing.
Attendees at the summit agreed a series of reforms on aid spending called the Grand Bargain, including a commitment to spend 25% of aid funds directly through local and national humanitarian aid organizations.

COVID-19 Pandemic
Following the outburst of the COVID-19 pandemic in 2019, approximately 216 million individuals required humanitarian aid across 69 countries. Many efforts and reforms of humanitarian assistance were made following the pandemic to the Covid-19 pandemic.

2020s: In 2020, there was an exponential increase in humanitarian needs, with 235 million people, or 1 in 33 individuals globally, requiring humanitarian assistance and protection by the year's end. A report documented an 85% increase in humanitarian air during 2020 then the year before.

See also: Church asylum
Emergency management
Humanitarian corridor
Humanitarian protection
Humanitarian Response Index
Vienna Declaration and Programme of Action
World Humanitarian Day

References: 

Further reading: Götz, Norbert; Brewis, Georgina; Werther, Steffen (2020). Humanitarianism in the Modern World: The Moral Economy of Famine Relief. Cambridge: Cambridge University Press. doi:10.1017/9781108655903. ISBN 978-1-108-65590-3.
James, Eric (2008). Managing Humanitarian Relief: An Operational Guide for NGOs. Rugby: Practical Action. Practical Action/Intermediate Technology.