Some spirits are associated with specific calendar dates, commonly known as their feast (whether or not any feasting is actually done).
A spirit’s feast is a day of power. If you have the luxury of choosing when to make an appeal, this is often the most advantageous time. Spirits are generally at the peak of their powers and generosity. They anticipate requests; their ears and hands are open. It is also the perfect time to fulfill vows and repay favors.
Spirits possessing feast days include African-Diaspora spirits such as the lwa or ori shas who are syncretized with Catholic saints. (See the Glossary entry for Syncretism.) Many East Asian, Hindu, Egyptian, Celtic, and Roman spirits also possess feasts. Roman spirits may possess multiple feasts; at least one usually commemorates the date an important shrine dedicated to that spirit was consecrated.
Dates for feasts at local shrines are included in individual entries, but be advised that customs are often updated faster and more spontaneously than books. Verify dates before making travel plans. Festivals of Asian spirits are determined by their own respective calendars, notnecessarily the standard Western calendar. References to Roman or other ancient feast days are by necessity approximations; calendars have changed many times since those festivals were outlawed.