Seen around 1685 and in used up to 1917, The “Green Ensign” was the unofficial Naval flag of Irish Merchant vessels. Prior to the 19th Century, it was a green field with a gold Irish Harp mounted center and left. The upper left quadrant (Canton), featured a white field with the red St. George Cross. After 1800. this was replace with the British Union Jack. Supposedly, The Green Ensign was not to “fly” without the British Union Jack (but often was). This may have been a deliberate act by Irish Sailors and Captains. It is not to be confused with The United Irishman Naval Jack (very similar is design and color).