In medieval Spain the existence of migratory flocks on the largest scale, which were carefully organised through the system of the "Mesta" gave rise to orderly drovers' roads, called "cabañeras" in Aragon, "carreradas" in Catalonia, "azadores reales", emphasising royal patronage, in Valencia, and most famous of all, "cañadas", including three major "cañadas reales", in Castile. Along these grazing trackways sheep travelled for distances of 350 to 450 miles (560 to 725 km), to the summer pasturages of the north, around León, Soria, Cuenca and Segovia, from the middle of April, and returning to winter pasturage in La Mancha, Estremadura, Alcántara and the lowlands of Andalusia.