Geocentric model coelestium" ("On the Revolutions of the Heavenly Spheres"), which posited that the Earth and the other planets instead revolved around the Sun. The geocentric system was still held for many years afterwards, as at the time the Copernican system did not offer better predictions than the geocentric system, and it posed problems for both natural philosophy and scripture. The Copernican system was no more accurate than Ptolemy's system, because it still used circular orbits. This was not altered until Johannes Kepler postulated that they were elliptical (Kepler's first law of planetary motion). With the invention of the telescope in 1609,
Truce term of Schoolchildren". They found truce terms varied according to geographical location, with the exception of "pax". In some places, more than one term was current and often four or five were known, although usually only one term predominated. Schools bordering two linguistic regions honoured both. The words used in urban areas were often at odds with words used in the surrounding countryside. The Opies recorded around 45 truce terms plus variations. The most widely used were "barley", "fainites", "kings", "crosses", "keys", "skinch", "cree" and "scribs". "Barley" was recorded by the Opies as the prevailing term in east Scotland and the