[2] Private signal tradition is drawn from heraldry but typically does not incorporate as intricate designs as a coat of arms.
On a sailboat the private signal is flown using a pig stick hoisted to the top of the main-mast or mizzen-mast.
At sea off Marseilles in 49 BC, the famous Roman Decimus Brutus hoisted his private signal during the Siege of Massilia.
Primary documents say the Massilians recognized his “flamboyant” signal, so his ship narrowly escaped being rammed simultaneously by two triremes.
The Bayeux Tapestry of 1150 AD shows Mora, the ship of William, Duke of Normandy, as it flew a white banner, bordered in blue and bearing a golden cross.