The illustration on the left shows the full coat of arms that was awarded in to Henry Fitzroy, 1st Duke of Grafton, the son of Charles II and the duchess of Cleveland. As you can see, the escutcheon is of Charles’ royal coat of arms, marred by the baton sinister. Thus, this represents that his father is the king, yet he is not able to be his heir.

And on the right is the coat of arms of his direct descendant, alive and well today, also named Henry Fitzroy… the 12th Duke of Grafton. You will notice that his shield (as well as the crest and supporters) still has exactly the same design as his ancestor!

Yes, this coat of arms tells us that he is a descendant of royalty, but the baton sinister confirms that he, and his family, have had no claim to the throne - in this case due to his illegitimate descent.

When James Scott, Duke of Monmouth, had his coat of arms created, something unusual happened… it didn’t include a marker of illegitimacy. Everyone knew that the king doted on his eldest son, and there were rumours that Charles might attempt to legitimise him. But to allow a bastard to wield royal arms without the correct indicators? That was unacceptable!

The design on the left shows Monmouth’s original arms, issued in 1663, at the same time he was created Duke of Monmouth, which were a creative reorganisation of the monarchical escutcheon.

After a few years, some complaining from the higher-ups, and Charles’ growing realisation that he would not legitimise Monmouth, a new design was created in 1667 which included the baton sinister.

But another addition would now have to be added: the escutcheon of Scott. Shortly after Monmouth was granted his original arms, he married Anna Scott, the heiress of the Buccleuch family, and as part of the marriage contract he took her name. As they were created Duke and Duchess of Buccleuch following the marriage, this element would also need to be incorporated into the new design.

The design on the right was Monmouth’s final coat of arms: the royal arms of Charles II, differenced with a baton sinister, and overlaid with an inescutcheon of pretence of the Scott heritage.

The Baton Sinister is not the exclusive marker of illegitimacy: although it has historically been the most popular way to difference an illegitimate child, it is not the only way..

When Charles Lennox, 1st Duke of Richmond and Lennox, was assigned his coat of arms, it was not a baton sinister that featured on his design, but a border of alternating red and white pieces, each white piece charged with a rose.

When 2nd Duke of Richmond and Lennox inherited the duchy of Aubigny, France upon his grandmother the Duchess of Portsmouth’s death, the inescutcheon of Aubigny was included on the redesign - which can be seen on the most recent version of the family coat of arms on the right.

This design has changed over the last few centuries. The most recent version on the right still holds the original design issued to Charles Lennox in the 1st and 4th grand quarters (with the Aubigny inescutcheon), but also includes the Lennox arms in the 2nd grand quarter, and the Gordon arms (which was added to the family dukedoms in 1876) in the 3rd grand quarter.