...porque ancha es castilla

Question

...porque ancha es castilla

What does this mean?

Answer 1

It means that the region known as ' castilla', nowadays ' Castilla y la Mancha' is wide ( big) . By which it means it's a big, open country , the horizons are long.

It also has a second meaning, in the open spaces of Castilla you're free to do what you please, i.e. you're out of sight.

I can't explain any better.

Answer 2

My take is that they may be talking about the Spanish language (castillano). In some areas, this can be referred to as "castilla". Without more context, I would say this means "because Spanish is widespread".