Two indispensable prerequisites for successful research in Romance etymology are sustained attention and patience. The worker is at liberty to select problems that suit his personal taste, to assemble a wealth of pertinent data, to examine solutions proposed in earlier inquiries, to cherish the idea of having found the clue to issues previously deemed insoluble. Yet this preparatory work, no matter how meticulously planned and conscientiously carried out, may not yield immediate results: the easily accessible data not infrequently form a vicious circle, the explanations of pioneer workers more often than not serve to confuse rather than to enlighten the present day explorer. With his entire apparatus of research ready for action at a moment's notice, the etymologist, in a state of protracted suspense, must withstand the temptation of prematurely declaring his work concluded. Patiently, humbly, yet with unfailing alertness, he must await the moment of great satisfaction when a chance find (perhaps a passage in a not readily available book or a record in a new dialect glossary) may supply the one unexpected form, usually a precious relic, which helps him to break the vicious circle and step out into the open. This newly discovered form will prove a priceless aid in the reconstruction of the bridge between Latin and Romance; not one of those hazardous suspension bridges on which some nineteenth century etymologists were fond of performing their acrobatics, but a solid, pleasant bridge, allowing for comfortable walking and an enjoyable view of the surrounding landscape. The history of Spanish terco and its cognates is apt to show how radically such a casual find can advance our knowledge.