In 1935, although there were hardly more than a dozen members of Opus Dei, St Josemaria contemplated its expansion from Madrid to other Spanish cities. The start of the Spanish Civil War in 1936, however, made it impossible to carry out these plans immediately. During the time the conflict lasted, St Josemaria carried on with his ministry; first in Madrid, at grave risk to his life, and later, in Burgos, after making a dangerous crossing of the Pyrenees mountains. In Burgos, he dedicated himself tirelessly to renewing contact with those who formed part of Opus Dei, and to his priestly activities. Taking advantage of the time he now had, St Josemaria decided to resume work on his doctoral dissertation in civil law, centering it not on the subject he had decided on before (the documents he had left in Madrid were practically lost) but on an interesting ecclesiastical reality that existed in Burgos: the quasi-episcopal jurisdiction of the Abbess of the Monastery of Las Huelgas. In 1942, he presented and defended his doctoral dissertation. Two years later, completing and amplifying his research, he published his third book, an extensive monograph on the Abbess of Las Huelgas.