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.

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.

His finances largely exhausted, he served as a mercenary in the Ottoman and Austrian armies before returning to England in 1858.

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.