I did not know anything of Saint Cecilia until putting together this little blog note regarding today. Check out the Wikipedia entry here!
For any non-Catholics reading, the Catholic Church has different days and seasons we celebrate different things. They aren't better or worse days than the rest of the days. They're just like birthdays or anniversaries when we choose to do something special or different in honor of someone or something. We can see this most notably with Advent and Lent for seasons and Christmas and Easter for days. Those are obviously big days because what we're celebrating was a big deal! Last Sunday, we celebrated the Feast of Christ the King. Many other days, such as this one, are designated to remember specific people of the past.
The calendar of saints is a traditional Christian method of organizing a liturgical year by associating each day with one or more saints and referring to the feast day of said saint. The system arose from the early Christian custom of annual commemoration of martyrs on the dates of their deaths, or birth into heaven, and is thus referred to in Latin as dies natalis ("day of birth"). Wikipedia.I will sometimes identify them on the blog, as they are fascinating to study and to good examples to remember.