The relationship betwen Spanish, Galician and Portuguese

From: David James
Message: 682
Date: 1999-12-28

Hi Everybody!
Sorry if this enquiry is slightly off topic but as an English speaker with a knowledge of Spanish it surprised me how much Galician I could understand during a recent trip tp north west Spain, whereas I can hardly understand any Portuguese at all. Am i correct in thinking that the grammar and vocabulary of Galician is almost identical to that of Portuguese and that many linguists regard Galician as dialect of Portuguese? Can Galicians generally understand the Portguese language? I have heard conflicting evidence regarding this point. Interestingly I have heard that the local Potuguese dialect of the Minho region of northern Portugal is called Galego although to my untrained ear it sounds completely different to the *Gallego* of Galicia.
One final question; if Galician and Potuguese share a common history at what point did they start to diverge and, hypothetically, if we were to travel back in time, say 500 years, to Portugal would the language sound more like Galician than conteporary Portuguese?
Thank you in advance
                       David (an interseted amateur).