The official Spanish records of the country which had been turned over to the United States Surveyor General at San Francisco consisted of four or five hundred volumes. To copy these, twelve Spaniards worked for a year under the direction of Mr. Savage,[40] "the greatest single effort" ever made in connection with the Bancroft enterprise. The mission records in possession of the archbishop of San Francisco were copied by Mr. Savage and three assistants in a month. In quest of data on Southern California, Bancroft and Oak took a trip to San Diego early in 1874, returning overland and visiting depositories of records. On this tour, Judge Benjamin Hays of San Diego turned over to Mr. Bancroft his historical collections, and subsequently directed the collecting in the south. The most efficient of the assistants employed by him was Edward F. Murray who, among other services, copied the records of the Santa Barbara missions. In March, 1877, Mr. Savage began work on the civil and ecclesiastical archives at Salinas, continuing the work at San José, Santa Cruz, and Sacramento. With others, he obtained dictations of the highest importance from native Californians and others, and in 1877 and 1878 spent eight months in that work, visiting all the missions from San Diego to San Juan Bautista with the exception of San Fernando and Purisima. While his aids were thus gathering the material upon which the History of California is founded, Mr. Bancroft, as he tells us (Lit. Ind., 657-663), was devoting his attention more especially to the gaining of information concerning the proceedings of the two vigilance committees that held sway in San Francisco in the "fifties," by no means an easy task, since the acts of both of these organizations were illegal and their surviving members could not be expected to talk very freely, even after a lapse of twenty years. After considerable urging, however, those who had custody of the records were induced in the interest of history to turn them over for Mr. Bancroft's inspection. This material was made use of in the supplemental volumes on Popular Tribunals; in the first writing of which Mr. Bancroft was himself engaged from 1875 to 1877. Like his manuscript for Central America, however, this work had to be revised before its publication ten years later. At an early date, Mr. Bancroft tells us (Lit. Ind., 623-628), he had corresponded with the heads of governments lying within his territory. The presidents of the Mexican and Central American republics and the governors of all the states had accorded him every facility. In 1874, especially favorable letters were received from the presidents of Salvador, Guatemala, and Nicaragua, the latter appointing a special commissioner to secure and ship documents.