Celtic knotwork Shamrock Pin

Shamrock, a three-leaved sprig, is derived from the Irish Seamróg and has been used as a symbol of Ireland since the 18th century. The shamrock as a symbol is also tied to Saint Patrick, Ireland's patron saint. It is said he used it as a metaphor for the Christian Holy Trinity, though the Celts had their own trinity Goddess before Christianity. The three Morrígna are Badb, Macha, and Nemain (sometimes Anand). The three Morrígna are also associated with the three land goddesses Ériu, Banba and Fódla.