Mahon, the eldest of four children, was born into a prominent Roman Catholic family in Ennis, County Clare.

His father, Patrick Mahon of New Park, participated in the Rebellion of 1798 while his mother, Barbara, was a significant heiress, being the only daughter of James O'Gorman of Ennis.

Christina was an heiress with property valued at £60,000 in her own right, which provided Mahon with the resources to pursue election to parliament.

[1] Born in a time when duelling was relatively common in Ireland, Mahon later claimed to have instigated and fought thirteen duels; and in these, to have been injured in six but to have drawn blood in seven.

[3] Parnell personally ensured Mahon was a candidate at the 1887 Carlow by-election, which he won at the age of 87 as a Nationalist.

There he associated with Charles Maurice de Talleyrand-Périgord, becoming a favourite at Louis-Philippe's court[1] and working as a journalist.

He travelled the world, spending time in both Africa, where he befriended Ferdinand de Lesseps, engineer of the Suez Canal,[2] and South America, before returning to Ireland in 1846.

[1] Following his defeat in the 1852 election, Mahon returned to Paris, then travelled on to St Petersburg, where he served in the Imperial Bodyguard.

He also claimed to have commanded a Chilean fleet during the Chincha Islands War and to have served as a colonel in Pedro II of Brazil's army.

[3] In 1866, he returned to Paris, where he was made a colonel in a regiment of chasseurs by Louis-Napoleon, but in 1877, he moved to Berlin, where he became a close associate of Otto von Bismarck.