An attempt to foment the enmity of the O'Donnells against him was frustrated by Shane's capture of Calvagh O'Donnell, whom he kept a close prisoner for nearly three years.
He divorced his first wife, a daughter of James MacDonnell, and treated his second, a sister of Calvagh O'Donnell, with gross cruelty in revenge for her brother's hostility; Calvagh himself, when Shane's prisoner, he subjected to continual torture; and Calvagh's wife, whom he made his mistress, and by whom he had several children, endured ill-usage at the hands of her drunken captor, who is said to have married her in 1565.
In spite of the traditional enmity between the O'Neills and the O'Donnells, Tyrone allied himself with Hugh Roe O'Donnell, nephew of Shane's former enemy Calvagh O'Donnell, and the two chieftains opened communications with Philip II.
In his later years Manus was troubled by quarrels between his sons Calvagh and Hugh MacManus; in 1555 he was made prisoner by Calvagh, who deposed him from all authority in Tyrconnel, and he died in 1564.
His first wife, Joan O'Reilly, was the mother of Calvagh, and two daughters, both of whom married O'Neills; the younger, Margaret, was wife of the famous rebel Shane O'Neill.
Calvagh O'Donnell (d.
Calvagh, acting apparently on the advice of his father, who was his prisoner and who remembered the successful night attack on Conn O'Neill at Knockavoe in 1522, surprised the O'Neills in their camp at night and routed them with the loss of all their spoils.
Calvagh was then recognized by the English government as lord of Tyrconnel; but in 1561 he and his wife were captured by Shane O'Neill in the monastery of Kildonnell.
His wife, Catherine Maclean, who had previously been the wife of the earl of Argyll, was kept by Shane O'Neill as his mistress and bore him several children, though grossly ill-treated by her savage captor; Calvagh himself was subjected to atrocious torture"during the three years that he remained O'Neill's prisoner.
In 1566 Sir Henry Sidney by the queen's orders marched to Tyrconnel and restored Calvagh to his rights.
Calvagh, however, died in the same year, and as his son Conn was a prisoner in the hands of Shane O'Neill, his half-brother Hugh MacManus was inaugurated The O'Donnell in his place.
Hugh, who in the family feud with Calvagh had allied himself with O'Neill, now turned round and combined with the English to crush the hereditary enemy of his family; and in 1567 he utterly routed Shane at Letterkenny with the loss of 1300 men, compelling him to seek refuge with the MacDonnells of Antrim, by whom he was treacherously put to death.