Alypius (flourished late 4th–5th century ad, Alexandria, Egypt) was the author of Eisagōgē mousikē (Introduction to Music), a work that contains tabular descriptions of two forms of ancient Greek notation; the tables indicate the interaction of the notation with the Greek modal system. Although the work was written well after the music in question, it is of fundamental importance in transcribing extant pieces into modern notation. The treatise survives incomplete; in its full form it may have contained additional information concerning Greek music theory. The earliest of the 34 surviving manuscripts is from the 12th century, yet the treatise was largely ignored until the late 16th century, when it drew the attention of Vincenzo Galilei (father of the astronomer Galileo) and his circle. The treatise was published in 1616 by Johannes Meursius, in excerpts in 1650 by Athanasius Kircher, and in 1652 by Marcus Meibom. The authoritative edition is by Karl von Jan in Musici scriptores graeci (1895, reprinted 1962; “Greek Writings on Music”).