History of physics to simplify their production. In heliocentric models of the Solar system, the Earth orbits the Sun along with other bodies in Earth's galaxy, a contradiction according to the Greek-Egyptian astronomer Ptolemy (2nd century CE; see above), whose system placed the Earth at the center of the Universe and had been accepted for over 1,400 years. The Greek astronomer Aristarchus of Samos (c.310 – c.230 BCE) had suggested that the Earth revolves around the Sun, but Copernicus' reasoning led to lasting general acceptance of this "revolutionary" idea. Copernicus' book presenting the theory ("De revolutionibus orbium coelestium", "On the Revolutions of the
Admiralty in the 16th century has organized the fleet into squadrons from at early 13th century and certainly during the 16th century. In 1560 three squadrons were operating in the Channel, Irish Sea and North Sea Until the 16th century, admirals were high officials under kings, and were charged with protecting the realm from sea attack. The English navy's Narrow Seas Squadron also called as the Eastern Squadron mainly operated in the two seas which laying between England and Kingdom of France (the English Channel particularly the Straits of Dover) and England and the Spanish Netherlands later the Dutch Republic (the southern North Sea). Include: