Thanks for mentioning "Vampire" as I was about to do the same.

One of the best modern scholars on the subject of the replacement of old pagan feast days and festivals with church-based holidays is Ronald Hutton; may I recommend hsi books The Rise and Fall of Merrie England and Stations of the Sun.

It is amusing to me that anyone doubts this...

Winter Solstice/Yule falls on December 20-22/Christmas is December 25th. A great many secular symbols prevail here (candles and lights--solstice is the rebirth of the light--or the sun or "the son"; frankincense had been sacred to solar gods well before the age of Christianity; trees, holly, mistletoe...)

Ostara/Eostre (feast of Teutonic spring fertility goddess) falls near full moon after spring equinox, as does EASTER (Eostre/easter???) and how about all those secular symbols we associate with easter which seem rather, ahem, fertile in their meaning (eggs, bunnies, flowers)?

Samhain (Gaelic for Summer's End)/Hallowe'en/All Saint's Day/All Soul's Day, on October 31 thru November 2: all are feasts/celebrations of the dead.