He is notable for being one of only two English officers of arms to have been born in the United States of America (Blanche Lyon Pursuivant Extraordinary Alexander Ochterlony, appointed in 1784, was the other).
John de Havilland's updated edition gives considerable detail to the lives of his own parents and grandparents with their heraldic coats of arms displayed in the margins.
John de Havilland explains that his maternal grandfather, William Ludwig von Sonntag, was born in Pforzheim (modern South West Germany) in 1745.
Captain William Ludwig von Sonntag was one of the 10,000 troops of King Louis XVI of France that were sent under the Count de Rochambeau to America to aid the Americans in their Revolutionary War against Great Britain.
Captain von Sonntag was present with his regiment at the siege of York-Town, in Virginia, where Lord Cornwallis surrendered, which virtually closed the war; the independence of the States being acknowledged soon after by Great Britain.
In statements by a Mr. C. Lamport sent to the Liberal Reform Club in Pall Mall London, General John de Havilland was said to have "voted for the Conservative candidates for the election for this division for the county.
The copy of the resolution also states that: "There can be no doubt that the action of the Committee was prompted by the Radical members of the Reform Club, who for a long time have made war upon those who still maintain the politics of its founders.
And General de Havilland having in January 1877 dedicated to Lord Beaconsfield a pamphlet entitled "England herself at Constantinople, the best solution of the Eastern Question," (since then we have acquired Cyprus and Egypt!)
As York Herald, de Havilland impaled these with his maternal arms of von Sonntag, blazoned "Azure a Sun in splendor proper" in the window of St Peter's Church, illustrated below, and used a Chief of Religion as a Knight of Malta in addition to setting his shield on the Maltese Cross.