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
Alexandria on the Caucasus the reign of Menander I the city was recorded as having a thriving Buddhist community, headed by Greek monks. In epic Sri Lankan poem Mahavamsa mentions the Greek (Pali: "Yona", lit: "Ionian") Buddhist monk Mahadhammarakkhita (), who is said to have come from “Alasandra” (thought to be Alexandria of the Caucasus), with 30,000 monks for the foundation ceremony of the Maha Thupa at Anuradhapura in Sri Lanka: Some archaeological evidence concerning Alexandria of the Caucasus was gathered by Charles Masson (1800–1853), providing insight into the history of that lost city. His findings include coins, rings, seals and other small objects.