Question: In English speaking countries of the Northern Hemisphere August 1 is known as Lammas Day, the festival of what? It is a custom to bring what to the church on this festival day.
Answer: It is the festival of the wheat harvest. It is custom to bring a loaf of bread made with the flour of the first-ripened wheat (or other grain) to Mass to be consecrated.
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https://www.almanac.com/fact/lammas-day-from-the-old-english-holiday#