Lucy Walter was born c.1630 at Roch Castle, Haverfordwest, into a family of middling gentry. During the English Civil war, she fled her home when it was destroyed by parliamentary forces. She sought refuge in London before travelling to The Hague.

It is suggested that Lucy turned to prostitution to support herself and was later ‘purchased’ for fifty gold pieces by Algernon Sidney, Earl of Leicester, a radical English republican. He was subsequently executed for treason and his brother, Colonel Robert Sidney ‘claimed’ Lucy as his property.

In 1648, described as ‘of no good fame, but handsome’, Lucy caught the attention of the eighteen-year-old Prince of Wales (later Charles II), who was at The Hague. On the 9 April 1649, their son, James, the future Duke of Monmouth, was born in Rotterdam and recognised by Charles as his natural son.In later life, James claimed that his parents had married, but this was denied by the crown.

In June 1650, Lucy had an affair with Theobald, 2nd Viscount Taaffe, and had a daughter, Mary, the following year. Abandoned by both men and described as ‘bold’ and an ‘embarrassment’, Lucy did not take her predicament lying down. Having spent four scandalous years in exile, she was persuaded to return to England from Cologne in 1656. She and her children were promised a pension of five thousand livres (£400) a year, but instead, she was promptly reported as a spy. As a result, she and her maid, Ann Hill, were arrested and sent to the Tower of London.

After her trial in June 1656, Lucy was discharged and deported back to the continent where, in Brussels, she resumed her extravagant lifestyle. After a botched attempt by the English Court to kidnap James, (described as a ‘great disturbance’ when a courtier attempted to snatch the boy from Lucy) she was ‘persuaded’ in March 1658 to hand him over to a royal tutor. One report states that ‘When Col. Slingsby succeeded in separating the mother from the boy (she) became desperate and created scenes which made the lot of those around her anything but pleasant.’ *

Later that year, Lucy died of venereal disease in Paris.

The ghost of Lucy Walker is now said to haunt Roch Castle, where witnesses claim to have seen her passing through closed doors and solid walls and wearing flowing white robes.

Ganed Lucy Walter tua 1630 yng Nghastell Roch, Hwlffordd, i deulu gweddol fonheddig.  Yn ystod Rhyfel Cartref Lloegr, gadawodd ei chartref wedi iddo gael ei ddinistrio gan luoedd seneddol.  Ceisiodd loches yn Llundain cyn teithio i’r Hague. 

Awgrymir i Lucy droi at buteindra i’w chefnogi ei hun, a’i bod wedi cael ei ‘phrynu’ yn ddiweddarach am hanner can darn o aur gan Algernon Sidney, Iarll Caerlŷr, gweriniaethwr radical o Loegr.  Wedi iddo gael ei ddienyddio am deyrnfradwriaeth, ‘hawliodd’ ei frawd, y Cyrnol Robert Sidney, Lucy fel ei eiddo yntau.

Yn 1648, disgrifiwyd Lucy fel menyw ‘heb fod yn fawr ei bri, ond yn deg o bryd’, a hawliodd sylw Tywysog Cymru, a oedd yn ddeunaw oed ar y pryd (ac a ddaeth i fod yn Siarl II), a oedd yn yr Hague.  Ar 9 Ebrill 1649, ganed eu mab, Iago, a fyddai’n dod yn Ddug Trefynwy, yn Rotterdam ac a gydnabuwyd gan Charles fel ei fab naturiol.Yn ddiweddarach, honnai Iago fod ei rieni wedi priodi, ond roedd y goron yn gwadu hyn.

Ym mis Mehefin 1650, cafodd Lucy garwriaeth gyda Theobald, 2il Is-iarll Taaffe, a ganed merch, Mary, y flwyddyn ganlynol. Gadawodd y ddau ddyn Lucy, a disgrifiwyd hi fel menyw ‘feiddgar’ ac ‘embaras‘, ond roedd yn benderfynol o frwydro ymlaen. Â hithau wedi treulio pedair blynedd mewn gwarth, fel alltud, perswadiwyd hi i ddychwelyd i Loegr o Cologne yn 1656. Gwnaed addewid iddi hi a’i phlant y byddent yn cael pensiwn o bum mil livre (£400) y flwyddyn, ond, yn hytrach, riportiwyd hi ar unwaith fel ysbïwraig. O ganlyniad, arestiwyd hi a’i morwyn, Ann Hill, ac anfonwyd y ddwy i Dŵr Llundain. 

Wedi ei threialu ym mis Mehefin 1656, rhyddhawyd Lucy a’i hallgludo yn ôl i’r cyfandir, lle ailgydiodd yn ei ffordd afradlon o fyw. Wedi i Lys Lloegr geisio cipio Iago’n aflwyddiannus, (gweithred a ddisgrifiwyd fel ‘styrbans sylweddol’ pan geisiodd gŵr llys gipio’r bachgen oddi ar Lucy) cafodd ei ‘pherswadio’ ym mis Mawrth 1658 i’w drosglwyddo at diwtor brenhinol. Mewn un adroddiad, dywedir ‘Pan lwyddodd y Cyrnol Slingsby i wahanu’r fam oddi wrth y bachgen, (aeth hi) yn gynddeiriog gan greu golygfeydd a oedd yn amhleserus iawn i’r rheiny o’i chwmpas.’

Yn nes ymlaen y flwyddyn honno, bu farw Lucy o glwyf gwenerol ym Mharis.

Erbyn hyn, dywedir bod ysbryd Lucy Walker yn aflonyddu ar Gastell Roch, lle mae tystion yn honni iddynt ei gweld yn pasio trwy ddrysau caeedig a waliau solid, gan wisgo gwisg laes, hir.