A number of kingdoms formed in present-day Wales in the post-Roman period. While the most powerful ruler was acknowledged as King of the Britons (later "Tywysog Cymru": "Leader" or "Prince of Wales"), and some rulers extended their control over other Welsh territories and into western England, none were able to unite Wales for long. Internecine struggles and external pressure from the English and later, the Norman conquerors of England, led to the Welsh kingdoms coming gradually under the sway of the English crown. In 1282, the death of Llywelyn ap Gruffudd led to the conquest of the Principality of Wales by King Edward I of England; afterwards, the heir apparent to the English monarch has borne the title "Prince of Wales". The Welsh launched several revolts against English rule, the last significant one being that led by Owain Glyndŵr in the early 15th century. In the 16th century Henry VIII, himself of Welsh extraction as a great grandson of Owen Tudor, passed the Laws in Wales Acts aiming to fully incorporate Wales into the Kingdom of England. Under England's authority, Wales became part of the Kingdom of Great Britain in 1707 and then the United Kingdom in 1801. Yet, the Welsh retained their language and culture despite heavy English dominance. The publication of the extremely significant first complete Welsh translation of the Bible by William Morgan in 1588 greatly advanced the position of Welsh as a literary language.