Legend has it that St. Patrick used the shamrock in the fifth century to symbolize the divine nature of the trinity when he introduced Christianity to Ireland.

The seamróg is a big part of Irish history, as the Shamrock was used as an emblem by the Irish Volunteers in the era of Grattan's Parliament in the 1770's, The Act of Union. When it became an emblem of rebellion in the 19th century, Queen Victoria made wearing a seamrog by member's of her regiments punishable by death by hanging. It was during this dark time that the phrase "the Wearing of the Green" began. Today the seamróg joins the English Rose and the Scottish Thistle on the British flag and is an integral part of Saint Patrick's Day celebrations.

"The Wearing of the Green" also symbolizes the birth of springtime. Irish legend states that green clothes attract faeries and aid crops.