While local commerce was common, long range interchanges—generally maintained by Hebrew merchants—were rare and appreciated. Monetary circulation was scarce, composed mainly of old Suebi and Visigothic coinage known locally as "solidos gallicianos". War and pillaging against the thriving Al-Andalus was also a very important source for the acquisition of riches, exotic items, and Muslim serfs. Later, pilgrimage of Christians from all over Europe to Santiago de Compostela brought not only riches, but also a range of continental innovations and trends, from shipbuilding, to new architectural styles such as Romanesque art.