The Coat of Arms of Dún Laoghaire–Rathdown, Ireland, as per the official blazon: 
Per chevron argent and vert, in chief an ancient Irish crown proper between in the dexter a slip of oak of the second fructed of the third and in the sinister a trefoil slipped also of the second, in base on waves of four of the first and azure a Viking longship sail set oars in action, also proper. 

Motto: Ó Chuan go Sliabh.
Own work
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