Despite his friendship with the Earl of Tyrone, his loyalty to the Crown was never seriously in doubt. However, after Tyrone's flight to the Continent in 1607, he was the target of vehement attacks by his enemies, especially the volatile and unreliable
Christopher St Lawrence, 10th Baron Howth, with whom he had quarrelled bitterly, despite being related to him by marriage. Lord Howth accused Moore of treasonable dealings with Tyrone, and pressed the charges with such vigour that the
Lord Lieutenant of Ireland, Sir
Arthur Chichester, who had originally laughed at them as "too absurd even to charge a horse-boy with, let alone a
knight", felt obliged to place Moore under
house arrest. Moore admitted that on the eve of the
Flight of the Earls, Tyrone had visited him at his home, Mellifont, but he firmly denied any imputation of
treason. Lord Howth, summoned before the Irish Council, refused to produce any evidence of the alleged treason, on the ground that since Moore was himself a Privy Councillor, that body was clearly guilty of
bias, while his bizarre claim that he had seen Moore trying to raise
the Devil did nothing to enhance his credibility. The case was transferred to England, and in due course, Moore was cleared of all suspicion. Howth, undaunted, now accused Chichester and Moore of conspiring to
murder him: the Council, which by now lost had all patience with Howth, ordered him to retire to his home in disgrace. Moore by contrast was assured that his loyalty to the King was not in question. ==Later career==