In April 1608 following the Flight of the Earls (14 September 1607), Sir Cahir O'Doherty the last Gaelic Lord of Inishowen and rebel leader lays siege to the City of Derry. He had been angered that his lands had been confiscated for the plantation of Ulster. While Sir Cahir was trying to capture Derry he sent Sir Niall Garve O'Donnell to Lifford castle to repel any attempt by the English to send reinforcements to Derry by the river crossing at Lifford. Niall Garve being greedy wanted to be close to the action and have a chance of getting a good share of the spoils when Derry would be sacked. He instead of going to Lifford went to Mongavlin Castle and evicted Ineen Dubh. Here he began plundering the local area and on hearing the news of Niall Garve's actions, Sir Cahir in turn evicted Niall Garve and reinstated Ineen Dubh in Mongavlin. Sir Cahir eventually sacks and burns Derry killing the Governor, Sir George Paulet in the process. Shortly after this the castle was abandoned due to the in-fighting of the O’Donnell clan.