The resumption of the Mongol invasion of Europe, during which the Mongols attacked medieval Rus' principalities and the powers of Poland and Hungary, was marked by the Mongol invasion of Rus' starting on 21 December 1237. The European invasion, indicated by the start of the Mongol invasion of Rus' marked by the Battle of the Kalka River (1223) which was fought between the scout forces of just the two Mongolian generals Subutai and Jebe, whose reconnaissance unit met in battle with the combined force of several Rus' princes.

The invasion, reinforced by the breakup of Kievan Rus' in the 12th century, had incalculable ramifications on the history of Eastern Europe, including the division of the East Slavic people into three separate nations and the rise of the Grand Duchy of Moscow.

After fifteen years of peace, the Rus' invasion was followed by Batu Khan's full-scale invasion of Rus' and points east during 1237 to 1240, which ended with a Mongol succession crisis. An alternative presents the European campaign as a pretense to keep the Europeans off balance and out of the Middle East.

The Invasion of Normandy was the invasion and establishment of Allied forces in Normandy, France, during Operation Overlord in 1944 during World War II. It was the largest amphibious operation ever to take place.

Allied land forces that saw combat in Normandy on 6 June came from Canada, the Free French Forces, the United Kingdom, and the United States. In the weeks following the invasion, Polish forces also participated, as well as contingents from Belgium, Czechoslovakia, Greece, and the Netherlands. Most of the above countries also provided air and naval support, as did the Royal Australian Air Force, the Royal New Zealand Air Force, and the Royal Norwegian Navy.

The Normandy invasion began with overnight parachute and glider landings, massive air attacks and naval bombardments. In the early morning, amphibious landings on five beaches codenamed Juno, Gold, Omaha, Utah, and Sword began and during the evening the remaining elements of the parachute divisions landed. The "D-Day" forces deployed from bases along the south coast of England, the most important of these being Portsmouth.

Mongol invasions progressed throughout the 13th century, resulting in the vast Mongol Empire which covered much of Asia and Eastern Europe by 1300.

The Mongol Empire emerged in the course of the 13th century by a series of conquests and invasions throughout Central and Western Asia, reaching Eastern Europe by the 1240s. The speed and extent of territorial expansion parallels the Hunnic/Turkic conquests of the Migration period (the 6th century Turkic Khaganate).

The territorial gains of the Mongols persisted into the 15th century in Persia (Timurid dynasty) and in Russia (Tatar and Mongol raids against Russian states), and into the 19th century in India (the Mughal Empire).

Genghis Khan forged the initial Mongol Empire in Central Asia, starting with the unification of the Mongol and Turkic central Asian confederations such as Merkits, Tartars, Mongols, and Uighurs. He then continued expansion of the Empire via invasion of the Khwarezmid Empire in what is modern-day Khorazm, Uzbekistan.

Large areas of Islamic Central Asia and northeastern Iran were seriously depopulated, as every city or town that resisted the Mongols was subject to destruction. In Termez, on the Oxus: "all the people, both men and women, were driven out onto the plain, and divided in accordance with their usual custom, then they were all slain". Each soldier was required to execute a certain number of persons, with the number varying according to circumstances. For example, after the conquest of Urgench, each Mongol warrior – in an army group that might have consisted of two tumens (units of 10,000) – was required to execute 24 people.