Euclid They follow the same logical structure as "Elements", with definitions and proved propositions. Other works are credibly attributed to Euclid, but have been lost. The European Space Agency's (ESA) Euclid spacecraft was named in his honor. 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
Ptolemy II Philadelphus in the Library of Alexandria to the Capodimonte Palace by Gioacchino Murat and then in 1867 moved to the Palazzo Reale di Napoli, before being given to the Camera dei deputati in Palazzo Montecitorio in Rome. It later returned to Naples and since 1997 has hung in its original position in Room 31 of the Royal Apartments, also known as the Salone della Culla. Ptolemy II Philadelphus in the Library of Alexandria Ptolemy Philadelphus in the Library of Alexandria is an 1813 oil on canvas painting by Vincenzo Camuccini. It is now in the National Museum of Capodimonte in Naples. The work was commissioned by