Charles XI of Sweden in the context of "Scanian War"

Peter III Fyodorovich (Russian: Пётр III Фёдорович, romanized: Pyotr III Fyodorovich; 21 February [O.S. 10 February] 1728 – 17 July [O.S. 6 July] 1762) was Emperor of Russia from 5 January 1762 until 9 July of the same year, when he was overthrown by his wife, Catherine II (the Great). He was born in the German city of Kiel as Charles Peter Ulrich of Schleswig-Holstein-Gottorp (German: Karl Peter Ulrich von Schleswig-Holstein-Gottorp), the grandson of Peter the Great and great-grandson of Charles XI of Sweden.

After a 186-day reign, Peter III was overthrown in a palace coup d'état orchestrated by his wife, and soon died under unclear circumstances. The official cause proposed by Catherine's new government was that he died due to hemorrhoids. This explanation was met with skepticism, both in Russia and abroad, with notable critics such as Voltaire and d'Alembert expressing doubt about the plausibility of death from such a condition.

From 1611 to 1721, Sweden was a European great power, becoming a dominant faction in the quest for control of the Baltic Sea and a formidable military power. During this period, known as Stormaktstiden ('The Great Power Era'), the Swedish Empire held a territory more than twice the size of its modern borders and one of the most successful military forces at the time, proving itself on numerous occasions on battlefields such as Wallhof, Narva, and Düna. The military of the Swedish empire is commonly (and wrongfully) recognized only as the Caroleans, which were in fact not in service until the late 17th century under Charles XI and his successor. The Swedish Empire and its modern military force was founded by Gustavus Adolphus, who inherited the throne in 1611 at age 17. He immediately reformed the common European military based on mercenaries to a professional national army. However, before completing his vision of conquering the Holy Roman Empire, the warrior king was killed in action in 1632. His daughter and successor did little to improve Sweden's military position and abdicated early, providing the Swedish Empire with a more warlike ruler. Charles X Gustav was only king for 5 years, but conquered large amounts of territory that still belong to Sweden today (including Blekinge, Bohuslän, Skåne, and Halland). His son Karl XI would further strengthen the army by introducing the Caroleans, which were also used by Karl XII in the Great Northern War.

However, despite great successes on the battlefield, an inadequate economy and limited manpower eventually led to the demise of the Swedish Empire, which ended its 110-year period as a great power in 1721.

Charles XII, sometimes Carl XII (Swedish: Karl XII) or Carolus Rex (17 June 1682 – 30 November 1718 O.S.), was King of Sweden from 1697 to 1718. He belonged to the House of Palatinate-Zweibrücken, a branch line of the House of Wittelsbach. Charles was the only surviving son of Charles XI and Ulrika Eleonora the Elder. He assumed power, after a seven-month caretaker government, at the age of fifteen.

In 1700, a triple alliance of Denmark–Norway, Saxony–Poland–Lithuania and Russia launched a threefold attack on the Swedish protectorate of Holstein-Gottorp and provinces of Livonia and Ingria, aiming to take advantage of the Swedish Empire being unaligned and ruled by a young and inexperienced king, thus initiating the Great Northern War. Leading the Swedish army against the alliance, Charles won multiple victories despite being significantly outnumbered. A major victory over a much larger Russian army in 1700, at the Battle of Narva, compelled Peter the Great to sue for peace, an offer that Charles subsequently rejected. By 1706, Charles, now 24 years old, had forced all of his foes into submission. That year, Swedish forces under general Carl Gustav Rehnskiöld won a decisive victory over a combined army of Saxony and Russia at the Battle of Fraustadt. Russia was now the sole remaining hostile power.

Caroleans (Swedish: karoliner), from Carolus, the Latin form of the name Charles, is a term used to describe soldiers of the Swedish army during the reigns of Kings Charles XI and Charles XII of Sweden, and specifically from 1680, when Charles XI instituted an absolute monarchy and embarked on a series of sweeping military reforms, to the death of Charles XII in 1718.

The Caroleans are particularly associated with Charles XII and his campaigns in the Great Northern War (1700–1721), during which they achieved a series of impressive victories, often against considerably larger enemy forces, and established themselves as one of the most feared and respected armies in Europe. However, the main Swedish field army was almost entirely annihilated after defeat at the Battle of Poltava, and the war eventually ended in utter defeat and the dissolution of the Swedish Empire.