 It was around this time in 1310, that Edward II of England granted John and his brothers their family's ancestral lands of Knapdale, provided they could recover it from Sir John Menteith.It is possible, therefore, that this event could have been the ""tryst of a fleet against Castle Sween"", recorded in the Book of the Dean of Lismore, which tells of the failed attempt by John MacSween to recapture Castle Sween.With the failure to recapture their lands in Scotland, the MacSweens were forced to permanently leave for Ireland.