via Olde English Pubs and the Signs of the Zodiac
Royal Oak – Robur Carolinum
Edmond Halley planted this constellation in the southern sky in 1678 as a patriotic gesture to his monarch, Charles II of England. It commemorated the oak tree in which King Charles hid after his defeat by Oliver Cromwell’s republican forces at the Battle of Worcester in 1651. Halley formed the constellation from stars that were previously part of Argo Navis.
Ref: http://www.ianridpath.com/startales/robur.htm
The Spirit World - Pub Astrology 