400. That’s an error.

Google cannot redirect you to http://worldcat.org/search?q=Coleccion+los+tratados+paz,+alianza,+neutralidad,+garantia+...+hechos+por+los+pueblos,+reyes+y+principes+España+con+los+pueblos,+reyes,+principes,+republicas+y+demás+potencias+Europa+... because the request was invalid.

This might be because the link was created a long time ago. Try your search again on Google. That’s all we know.