Editing Library of Alexandria (section)

===Peak of literary criticism===
[[File:Alexandria - Pompey's Pillar - view of ruins.JPG|thumb|Present-day ruins of the [[Serapeum of Alexandria]], where the Library of Alexandria moved part of its collection after it ran out of storage space in the main building{{sfn|MacLeod|2000|page=5}}]]

[[Aristophanes of Byzantium]] (lived {{circa}} 257–{{circa}} 180 BC) became the fourth head librarian sometime around 200 BC.{{sfn|Casson|2001|page=38}} According to a legend recorded by the Roman writer [[Vitruvius]], Aristophanes was one of seven judges appointed for a poetry competition hosted by Ptolemy III Euergetes.{{sfn|Casson|2001|page=38}}{{sfn|McKeown|2013|pages=148–149}} All six of the other judges favored one competitor, but Aristophanes favored the one whom the audience had liked the least.{{sfn|Casson|2001|page=38}}{{sfn|McKeown|2013|page=149}} Aristophanes declared that all of the poets except for the one he had chosen had committed plagiarism and were therefore disqualified.{{sfn|Casson|2001|page=38}}{{sfn|McKeown|2013|page=149}} The king demanded that he prove this, so he retrieved the texts that the authors had plagiarized from the Library, locating them by memory.{{sfn|Casson|2001|page=38}}{{sfn|McKeown|2013|page=149}} On account of his impressive memory and diligence, Ptolemy III appointed him as head librarian.{{sfn|McKeown|2013|page=149}}

The librarianship of Aristophanes of Byzantium is widely considered to have opened a more mature phase of scholarship in the Library of Alexandria's history.{{sfn|Dickey|2007|page=5}}{{sfn|Montana|2015|page=118}}{{sfn|MacLeod|2000|page=7}} During this phase, [[literary criticism]] reached its peak{{sfn|Dickey|2007|page=5}}{{sfn|Montana|2015|page=118}} and came to dominate the Library's scholarly output.{{sfn|MacLeod|2000|pages=7–8}} Aristophanes of Byzantium edited poetic texts and introduced the division of poems into separate lines on the page, since they had previously been written out just like prose.{{sfn|Dickey|2007|pages=5, 93}} He also invented the system of [[Greek diacritics]],{{sfn|Dickey|2007|pages=5, 92–93}}{{sfn|MacLeod|2000|page=7}} wrote important works on [[lexicography]],{{sfn|Dickey|2007|page=5}} and introduced a series of signs for textual criticism.{{sfn|Dickey|2007|page=93}} He wrote introductions to many plays, some of which have survived in partially rewritten forms.{{sfn|Dickey|2007|page=5}}

The fifth head librarian was an obscure individual named [[Apollonius Eidographus]], who is known by the epithet {{langx|grc|ὁ εἰδογράφος}} ("the classifier of forms").{{sfn|Dickey|2007|page=5}}{{sfn|Montana|2015|page=129}} One late lexicographical source explains this epithet as referring to the classification of poetry on the basis of musical forms.{{sfn|Montana|2015|page=129}}

During the early second century BC, several scholars at the Library of Alexandria studied works on medicine.{{sfn|Montana|2015|page=117}} Zeuxis the Empiricist is credited with having written commentaries on the Hippocratic Corpus{{sfn|Montana|2015|page=117}} and he actively worked to procure medical writings for the Library's collection.{{sfn|Montana|2015|page=117}} A scholar named Ptolemy Epithetes wrote a treatise on wounds in the Homeric poems, a subject straddling the line between traditional philology and medicine.{{sfn|Montana|2015|page=117}} However, it was also during the early second century BC that the political power of Ptolemaic Egypt began to decline.{{sfn|Meyboom|1995|page=173}} After the [[Battle of Raphia]] in 217 BC, Ptolemaic power became increasingly unstable.{{sfn|Meyboom|1995|page=173}} There were uprisings among segments of the Egyptian population and, in the first half of the second century BC, connection with [[Upper Egypt]] became largely disrupted.{{sfn|Meyboom|1995|page=173}} Ptolemaic rulers also began to emphasize the Egyptian aspect of their nation over the Greek aspect.{{sfn|Meyboom|1995|page=173}} Consequently, many Greek scholars began to leave Alexandria for safer countries with more generous patronages.{{sfn|Dickey|2007|page=5}}{{sfn|Meyboom|1995|page=173}}

[[Aristarchus of Samothrace]] (lived {{circa}} 216–{{circa}} 145 BC) was the sixth head librarian.{{sfn|Dickey|2007|page=5}} He earned a reputation as the greatest of all ancient scholars and produced not only texts of classic poems and works of prose, but full ''[[hypomnema]]ta'', or long, free-standing commentaries, on them.{{sfn|Dickey|2007|page=5}} These commentaries would typically cite a passage of a classical text, explain its meaning, define any unusual words used in it, and comment on whether the words in the passage were really those used by the original author or if they were later interpolations added by scribes.{{sfn|Casson|2001|page=43}} He made many contributions to a variety of studies, but particularly the study of the Homeric poems,{{sfn|Dickey|2007|page=5}} and his editorial opinions are widely quoted by ancient authors as authoritative.{{sfn|Dickey|2007|page=5}} A portion of one of Aristarchus' commentaries on the ''[[Histories (Herodotus)|Histories]]'' of [[Herodotus]] has survived in a papyrus fragment.{{sfn|Dickey|2007|page=5}}{{sfn|Casson|2001|page=43}} In 145 BC, however, Aristarchus became caught up in a dynastic struggle in which he supported [[Ptolemy VII Neos Philopator]] as the ruler of Egypt.{{sfn|Montana|2015|page=130}} Ptolemy VII was murdered and succeeded by [[Ptolemy VIII Physcon]], who immediately set about punishing all those who had supported his predecessor, forcing Aristarchus to flee Egypt and take refuge on the island of [[Cyprus]], where he died shortly after.{{sfn|Montana|2015|page=130}}{{sfn|Dickey|2007|page=5}} Ptolemy VIII expelled all foreign scholars from Alexandria, forcing them to disperse across the Eastern Mediterranean.{{sfn|Dickey|2007|page=5}}{{sfn|Meyboom|1995|page=173}}