Parallel (geometry) as a pair of straight lines in a plane which do not meet appears as Definition 23 in Book I of Euclid's Elements. Alternative definitions were discussed by other Greeks, often as part of an attempt to prove the parallel postulate. Proclus attributes a definition of parallel lines as equidistant lines to Posidonius and quotes Geminus in a similar vein. Simplicius also mentions Posidonius' definition as well as its modification by the philosopher Aganis. At the end of the nineteenth century, in England, Euclid's Elements was still the standard textbook in secondary schools. The traditional treatment of geometry was being
Aristobulus of Alexandria quoted by Anatolius. He is incorrectly named "Aristobulus of Paneas" in Rufinus' Latin translation of Eusebius' "Historia Ecclesiastica" (7, 32, 16). It is a wrong translation of the Greek ὁ πάνυ, "the Great". In addition, the author here quoted by Eusebius, Anatolius of Laodicea (270 CE), was mistaken in believing that Aristobulus was one of the 70 priests who translated the Torah into Greek (the "Septuagint") during the reign of Ptolemy II Philadelphus (3rd century BC). Anatolius of Laodicea incorrectly said that he lived in the time of Ptolemy Philadelphus. A further mistake in Rufinus' Latin translation of the Anatolius