Pytheas made a voyage of exploration to northwestern Europe in about 325 BC, but his account of it, known widely in Antiquity, has not survived and is now known only through the writings of others. On this voyage, he circumnavigated and visited a considerable part of modern-day Great Britain and Ireland. He was the first known scientific visitor to see and describe the Celtic and Germanic tribes. "Britain" is most like Welsh "Ynys Prydein", "the island of Britain", in which is a P-Celtic allophone of Q-Celtic Cruithne in Irish "Cruithen-tuath", "land of the Picts". The base word is Scottish/Irish "cruth", Welsh "pryd", meaning "form". The British were the "people of forms", with the sense of shapes or pictures, thought to refer to their practice of tattooing or war painting. The Roman word "Picti", "the Picts", means "painted". This etymology shows that Pytheas interacted not so much with Irish, as they used Q-Celtic. Rather, Pytheas brought back the P-Celtic form from more geographically accessible regions where Welsh or Breton are spoken presently. Furthermore, some proto-Celtic was spoken over all of Greater Britain, and this particular spelling is prototypical of those more populous regions. Diodorus, based on Pytheas reports that Britain is cold and subject to frosts, being "too much subject to the Bear", and not "under the Arctic pole", as some translations say.