Euclid Euclid Euclid (; – "Eukleídēs", ; fl. 300 BC), sometimes given the name Euclid of Alexandria to distinguish him from Euclides of Megara, was a Greek mathematician, often referred to as the "founder of geometry" or the "father of geometry". He was active in Alexandria during the reign of Ptolemy I (323–283 BC). His "Elements" is one of the most influential works in the history of mathematics, serving as the main textbook for teaching mathematics (especially geometry) from the time of its publication until the late 19th or early 20th century. In the "Elements", Euclid deduced the theorems of what
Ptolemy (name) Ptolemy (name) The name Ptolemy or Ptolemaeus may refer to: Ptolemy, or Ptolemaeus, or Tolomeo (Italian spelling) may also refer to: According to Georg Autenrieth, the English name Ptolemy comes from the Ancient Greek name Πτολεμαῖος ("Ptolemaios"), "warlike" or "son of war". Autienrieth renders the meaning of the name to be an adjective from πτόλεμος ("ptólemos"), explained as a Homeric Greek form of πόλεμος ("pólemos"), "war". A nephew of Antigonus I Monophthalmus was called "Polemaeus", the normal form of the adjective. "Ptolemaios" is first attested in Homer's Iliad and is the name of an Achaean warrior, son of Piraeus, father