[5][6] The House was founded in the 14th century by William Fleetwood from whom all members descend.

The later, was a king of Gwynedd who reigned in 1137 to his death in November 1169 and was married to Gwladys ap Llywarch, a daughter and heir of L'Loworth.

[6] As such, the English family originates in Heskin, Lancashire, but it was of little importance until the 16th century, when Thomas Fleetwood and his three brothers moved south.

[9] A genealogy chart perused by William Segar, Garter Principal King of Arms,[10] on 19 June 1632, is kept in deposit by the Nordic Museum.

An excerpt below starting with Edward Fleetwood: Sir George was knighted 3 June 1632 by the Swedish King Gustav II Adolf;[5] created a Swedish baron 1 June 1654 at Uppsala Castle by Queen Christina,[18] and was introduced into the House of Nobility on 19 June 1654 as Baronial family No 49 with the following blazon: [..] Quarterly with an inescutcheon with the former Fleetwood weapon; in the uppermost quarter on the left and lowest on right an upright standing lion of red color in a field argent; In the upper one on the right and the last Shield on the left a crown in gold in field azure.