than System B. While it thus appears that System A preceded System B, both systems remained in use at least until the 1st century BC. The earliest preserved System A clay tablets (BM 36651, 36719, 37032, 37053) calculate an ephemeris for the planet Mercury from 424 to 401 BC. The oldest preserved lunar tablets date from 306 BC in the Hellenistic period. If Naburimannu was the originator of System A, then we can on that basis place him in Babylonia sometime between the Persian and Macedonian conquests. References Otto E. Neugebauer: A History of Ancient Mathematical Astronomy Part Two IV A 4, 4A (p. 611). Springer, Heidelberg 1975 (reprinted 2004). Otto E. Neugebauer: Astronomical Cuneiform Texts. 3 volumes. London: 1956; 2nd edition, New York: Springer, 1983. (Commonly abbreviated as ACT): Vol.I pp. 12,13 Herman Hunger and David Pingree: Astral Sciences in Mesopotamia pp. 215–217, 224, 258, 264. Brill, Leiden 1999. External links A. Braeken, V. Nikov, and S. Nikova, "Zigzag Functions and Related Objects in New Metric" Luboš Motl's Reference Frame: Maldacena in the Lineland (defines and discusses zig-zag functions) Babylonian astronomers People from the Achaemenid Empire 6th-century BC people