The Eighty Years' War, or Dutch War of Independence, (1568–1648), began as a revolt of the Seventeen Provinces against Philip II of Spain, the sovereign of the Habsburg Netherlands.

After the initial stages, Philip II deployed his armies and regained control over most of the rebelling provinces. However, under the leadership of the exiled William of Orange, the northern provinces continued their resistance and managed to oust the Habsburg armies, and established the Republic of the Seven United Netherlands. The subsequent war continued, although the heartland of the republic was no longer threatened. The war ended in 1648 with the Peace of Münster, when the Dutch Republic was recognised as an independent country.

In the decades leading to the war, the Dutch had become increasingly discontented with Habsburg rule. A major cause of Dutch discontent was the heavy level of taxation the population was required to pay, while support and guidance from the government was hampered by the size of the empire. At that time the Seventeen Provinces were known in the Habsburg empire as De landen van herwaarts over, and in French Les pays de par deça ("those lands around there"). In practice this meant that the Dutch provinces were being continually criticized for acting without permission from the throne, while the latter was not practical since any request for permission sent to the throne would take at least four weeks for a response to return. This unrest was further amplified by the presence of Spanish troops brought in to oversee the order in these provinces.^{[citation needed]}

Various wars have been named after their approximate duration:

Carl Edward Sagan ( /ˈseɪɡɪn/; November 9, 1934 – December 20, 1996) was an American astronomer, astrophysicist, cosmologist, author, science popularizer, and science communicator in astronomy and natural sciences. He published more than 600 scientific papers and articles and was author, co-author or editor of more than 20 books. He advocated scientifically skeptical inquiry and the scientific method, pioneered exobiology and promoted the Search for Extra-Terrestrial Intelligence (SETI).

Sagan is known for his popular science books and for the award-winning 1980 television series Cosmos: A Personal Voyage, which he narrated and co-wrote. The book Cosmos was published to accompany the series. Sagan wrote the novel Contact, the basis for a 1997 film of the same name.

Carl Sagan was born in Brooklyn, New York, to a Ukrainian Jewish family. His father, Sam Sagan, was an immigrant garment worker from Kamenets-Podolsk, Ukraine; his mother, Rachel Molly Gruber, a housewife. Carl was named in honor of Rachel's biological mother, Chaiya Clara, in Sagan's words, "the mother she never knew." Sagan graduated from Rahway High School in Rahway, New Jersey, in 1951.