The Greek sexagesimal placeholder or zero symbol changed over time. The symbol used on papyri during the second century was a very small circle with an overbar several diameters long, terminated or not at both ends in various ways. Later, the overbar shortened to only one diameter, similar to the modern "o" macron (ō) which was still being used in late medieval Arabic manuscripts whenever alphabetic numerals were used. But the overbar was omitted in Byzantine manuscripts, leaving a bare "ο" (omicron). This gradual change from an invented symbol to "ο" does not support the hypothesis that the latter was the initial of οὐδέν meaning "nothing". Note that the letter "ο" was still used with its original numerical value of 70; however, there was no ambiguity, as 70 could not appear in the fractional part of a number, and zero was usually omitted when it was the integer.