Lo, I shall tell you the truest of visions, a dream that I dreamt in the dead of night while people reposed in peaceful sleep. I seemed to see the sacred tree, lifted on high in a halo of light, the brightest of beams; that beacon was wholly gorgeous with gold; glorious gems stood fair at the foot; and five were assembled, at the crossing of the arms. The angels of God looked on.... - The Dream of the Rood
St Berin, often Latinised as Birinus (c600-650), was a Frankish missionary venerated in the Catholic, Orthodox and Anglican churches as "the Apostle of Wessex". He baptised Cynegils, the first Christian king of the Gewissae, near his "capital" at Dorchester-on-Thames.
Conversion to Christianity at the time was about more than the state of the king's soul. It meant joining a growing commonwealth of nations instead of looking inwards. It also boosted the transition from an oral to a written culture - a boon to historians, who now have textual as well as archaeological evidence to work from.
Written records also kickstarted a trend for royal genealogies which uncovered (or invented) connections between kingdoms and royal families. Berin and Cynegils could therefore be said to have helped turn the Gewissae from an isolated war-band to a European nation.