It was published in parts between 1883 and 1888 in Leipzig, Germany by Teubner, who still publishes Latin and Greek editions to be used by scholars. These symbols indicate the names of the corresponding manuscripts of Euclid that have been found. The preface, notes and abbreviations of all Teubner editions are still written in Latin, even though the books are printed in Germany. Hand copying was formerly the only way to make copies of a book. The printing press revolutionized the transmission of information in its time as much as the computer has in our own.
Every manuscript has a story to tell.
This particular manuscript, P, is very important. It was discovered in Rome in 1808 by F. Peyrard, a Frenchman, in the library of the Vatican. At the time, Napoleon was collecting manuscripts from Italy and sending them back to Paris. 190 turned out to be quite different from other versions and was proven to be more reliable. On page 1 you see the beginning of the actual Greek in a sort of Italics.