The Crowleys of Ballymacoda were ordinary County Cork farmers, but the granduncle's story had marked the family. Father Peter O'Neill had taken part in the 1798 Rebellion against British rule, been flogged for it, and transported to Botany Bay - the convict settlement in New South Wales that swallowed thousands of Irish rebels in the early 19th century. Peter O'Neill Crowley, born in 1832, inherited that memory along with the farm. He joined the Irish Republican Brotherhood, the secret society known to history as the Fenians, and built up a local company of roughly a hundred men in Ballymacoda. A teetotaller in a country where the recruitment officer's bottle had ruined many a rebel cell, he was the kind of leader who took the discipline as seriously as the politics.

On 5 March 1867, the Irish Republican Brotherhood launched its long-planned national rising. Under Captain John McClure, O'Neill Crowley led the attack on the Killadoon coastguard station to seize its weapons. The raid succeeded. The Fenians took the weapons and marched towards Killeagh with their captured RIC prisoners, expecting to link up with rebel units coming north from Youghal and east from Midleton. The reinforcements never came. The rising had failed in East Cork as it failed almost everywhere else - undermined by heavy snow, by informers in the local IRB networks, and by simple bad luck. McClure made the only practical decision left: disband all unarmed men, march the rest to Castlemartyr, release the prisoners, and try to slip away. He and O'Neill Crowley and a small group of comrades took refuge in Kilclooney Wood.

They lasted twenty-six days in the wood. On 31 March 1867, British soldiers tracked them down. The fight in the woodland was sharp and uneven. O'Neill Crowley was hit; the surviving Fenians were captured and marched to Mitchelstown. He died there of his wounds, seven weeks short of his 35th birthday. The British had won decisively, but they had also handed the IRB a martyr. A nationalist movement that had failed in arms now had a face - a young teetotaller farmer who had stood by his comrades when escape was still possible. Songs began to be written about him almost immediately. "As I rambled out one evening, all in the month of June," begins one, "I strayed into an old churchyard to view a noble tomb." The verses go on about the green woods of Kilclooney and the brave old oak where Crowley fell. They are still sung.

Visit any town in East Cork or its hinterland and you can find Peter O'Neill Crowley's name attached to a piece of public infrastructure. O'Neill Crowley Terrace in Mitchelstown, where he died. O'Neill Crowley Street in Youghal, the town he had hoped would rise to meet him. O'Neill-Crowley Quay along the Blackwater in Fermoy. O'Neill Crowley Terrace in Castlemartyr, where the Fenians had released their prisoners. In 1898, on the 31st anniversary of his death, a stone monument was erected at Sraharla on the road to Kilfinane, near Kilclooney Wood. Commemorations followed in 1967 - the centenary - and again in 2000. A viewing platform was added at the site in 2013. A statue of him forms part of the National Monument on Grand Parade in Cork city, surrounded by figures from earlier generations of Irish nationalism.

He turns up in another rebel song too. "Erin's Lovely Lee" describes a meeting between two old comrades, one of whom is asked: "Could you tell where Crowley fell, his native land to free?" The reply is plain: "'Tis I can tell where Crowley fell, 'twas in Kilclooney Woods." The political project Peter O'Neill Crowley died for took another fifty-five years to be even partially realised - the Treaty that created the Irish Free State was signed in 1922. By then the Fenian rebels of 1867 had been folded into the longer mythology of Irish republicanism, where they sit alongside the United Irishmen of 1798, the Land League, the men of Easter 1916, and the volunteers of the War of Independence. Crowley's granduncle was flogged for taking part in the first; he himself died trying for the second. The streets and quays of East Cork still carry his name into the third century after his death.