 Mesta flocks followed a seasonal pattern of transhumance across Spain . In the spring , they left the winter pastures ( <unk> ) in Extremadura and Andalusia to graze on their summer pastures ( <unk> ) in Castile , returning again in the autumn . Spanish rulers eager to increase wool profits gave extensive legal rights to the Mesta , often to the detriment of local peasantry . The huge merino flocks had a lawful right of way for their migratory routes ( <unk> ) . Towns and villages were obliged by law to let the flocks graze on their common land , and the Mesta had its own sheriffs that could summon offending individuals to its own tribunals . 
