Complex sentence: Irish mythology tells us that Samhain was one of the four seasonal festivals of the year, and the 10th-century tale "Tochmarc Emire" ('The Wooing of Emer') lists Samhain as the first of these four "quarter days".
Split into simpler sentences: Irish mythology tells us that Samhain was one of the four seasonal festivals of the year. The 10th-century tale "Tochmarc Emire" ('The Wooing of Emer') lists Samhain as the first of these four "quarter days".