Year Without a Summer in the context of "Peterloo Massacre"

The Minoan eruption was a catastrophic volcanic eruption that devastated the Aegean island of Thera (also called Santorini) circa 1600 BC. It destroyed the Minoan settlement at Akrotiri, as well as communities and agricultural areas on nearby islands and the coast of Crete with subsequent earthquakes and tsunamis. With a Volcanic Explosivity Index (VEI) of 7, it resulted in the ejection of approximately 28–41 km (6.7–9.8 cu mi) of dense-rock equivalent (DRE), the eruption was one of the largest volcanic events in human history. Because tephra from the Minoan eruption serves as a marker horizon in nearly all archaeological sites in the Eastern Mediterranean, its precise date is of high importance and has been fiercely debated among archaeologists and volcanologists for decades, without coming to a definite conclusion.

Although there are no clear ancient records of the eruption, its plume and volcanic lightning may have been described in the Egyptian Tempest Stele. The Chinese Bamboo Annals reported unusual yellow skies and summer frost at the beginning of the Shang dynasty, which may have been a consequence of volcanic winter (similar to 1816, the Year Without a Summer, after the 1815 eruption of Mount Tambora).

In April 1815, Mount Tambora, a volcano on the island of Sumbawa in present-day Indonesia (then part of the Dutch East Indies), erupted in what is now considered the most powerful volcanic eruption in recorded human history. This eruption, with a volcanic explosivity index (VEI) of 7, ejected 37–45 km (8.9–10.8 cubic miles) of dense-rock equivalent (DRE) material into the atmosphere, and was the most recent confirmed VEI-7 eruption.

Although the Mount Tambora eruption reached a violent climax on 10 April 1815, increased steaming and small phreatic eruptions occurred during the next six months to three years. The ash from the eruption column dispersed around the world and lowered global temperatures in an event sometimes known as the Year Without a Summer in 1816. This brief period of significant climate change triggered extreme weather and harvest failures in many areas around the world. Several climate forcings coincided and interacted in a systematic manner that has not been observed after any other large volcanic eruption since the early Stone Age.

The Regency era of British history is commonly understood as the years between c. 1795 and 1837, although the official regency for which it is named only spanned the years 1811 to 1820. King George III first suffered debilitating illness in the late 1780s, and relapsed into his final mental illness in 1810. By the Regency Act 1811, his eldest son George, Prince of Wales, was appointed Prince Regent to discharge royal functions. The Prince had been a major force in Society for decades. When George III died in 1820, the Prince Regent succeeded him as George IV. In terms of periodisation, the longer timespan is roughly the final third of the Georgian era (1714–1837), encompassing the last 25 years or so of George III's reign, including the official Regency, and the complete reigns of both George IV and his brother and successor William IV. It ends with the accession of Queen Victoria in June 1837 and is followed by the Victorian era (1837–1901).

Although the Regency era is remembered as a time of refinement and culture, that was the preserve of the wealthy few, especially those in the Prince Regent's own social circle. For the masses, poverty was rampant as urban population density rose due to industrial labour migration. City dwellers lived in increasingly larger slums, a state of affairs severely aggravated by the combined impact of war, economic collapse, mass unemployment, a bad harvest in 1816 (the "Year Without a Summer"), and an ongoing population boom. Political response to the crisis included the Corn Laws, the Peterloo Massacre, and the Representation of the People Act 1832. Led by William Wilberforce, there was increasing support for the abolitionist cause during the Regency era, culminating in passage of the Slave Trade Act 1807 and the Slavery Abolition Act 1833.

1816 (MDCCCXVI) was a leap year starting on Monday of the Gregorian calendar and a leap year starting on Saturday of the Julian calendar, the 1816th year of the Common Era (CE) and Anno Domini (AD) designations, the 816th year of the 2nd millennium, the 16th year of the 19th century, and the 7th year of the 1810s decade. As of the start of 1816, the Gregorian calendar was 12 days ahead of the Julian calendar, which remained in localized use until 1923.

This year was known as the Year Without a Summer, because of low temperatures in the Northern Hemisphere, possibly the result of the 1815 eruption of Mount Tambora in Indonesia, causing severe global cooling, catastrophic in some locations.

Mount Tambora, or Tomboro, is an active stratovolcano in West Nusa Tenggara, Indonesia. Located on Sumbawa in the Lesser Sunda Islands, volcanism is the result of subduction zones. The 1815 eruption was the largest in recorded history, erupting up to 150 cubic kilometers of volcanic material, making it a VEI-7 on the Volcanic explosivity index. This caused the summer of 1816 to become known as the "Year Without a Summer" due to global cooling from the eruption.

The 1810s (pronounced "eighteen-tens") was a decade of the Gregorian calendar that began on January 1, 1810, and ended on December 31, 1819.

The decade was opened with a very hostile political climate around the world. Napoleon was invading France's neighbours in efforts to build a French Empire, causing a chain of global-scaled conflicts known as the Napoleonic Wars. Here, France's Napoleonic empire saw its rise and fall through events such as Napoleon's attempts to conquer Russia, the War of 1812 (spillover to America), and the Battle of Waterloo (Napoleon's ultimate defeat). Imperialism began to encroach towards African and Asian territories through trade, as the United States saw mass-scaled migration that headed westward towards the American frontier (mostly through the opening of the Oregon Trail.)