In 1759, their eldest daughter, Anne, married the then 2nd Baron Mornington (who, in 1760, was created the 1st Earl of Mornington) and herself bore two sons and a daughter – Penelope Prudence, Richard and Arthur, the future Duke of Wellington.
The school also possesses an oil painting of the area as it was at the time of Wellington and reputedly shows the famous Molly Ward's Tavern, an important meeting place during the time of the United Irishmen.
Annadale Grammar School colours were red, black and white.
The school song was "De Brevitate Vitae (On the Shortness of Life)", perhaps more commonly known by its first words "Gaudeamus Igitur (Let Us Therefore Rejoice)".
The four school houses were named after Irish generals in the Second World War (all of them Ulstermen or of Ulster origin): Alexander; Alanbrooke; Dill; Montgomery.