Who knows three hundred and three?
?שלושה ושלוש מאות - מי יודע
In the spirit of the song "Echad - mi yodeya", please post interesting and significant Jewish facts about the number 303.
Lazy gematria on this one is not worth approaching.
Check out mi-yodeya-series for the previous three hundred and two entries in this ongoing series.
Please include sources for your information wherever possible, as with all other answers on this site.