“ Jaca is an episcopal see, and was formerly the capital of the Aragonese county of Sobrarbe. Its massive Gothic cathedral dates at least from the 11th century, and possibly from the 9th. The city derives some importance from its position on the ancient frontier road from Saragossa to Pau. In August 1904 the French and Spanish governments agreed to supplement this trade-route by building a railway from Oloron in the Basses Pyrénées to Jaca. Various frontier defence works were constructed in the neighbourhood at the close of the 19th century. ”