County Wicklow was established in 1606 and the Dublin Castle administration sought to contain the threat to English planters from the Gaelic O'Toole and O'Byrne clans in the mountains. A fort was built at Macreddin while Henry Cary, 1st Viscount Falkland was Lord Deputy of Ireland in 1625-28, and named "Cary's fort" in his honour. Samuel Lewis records that the garrison was withdrawn to Dublin in the 1641 Rebellion and the site was captured from the English by the O'Byrnes. No visible trace of the fort remains; the site is reputed to be in "Castle Field".