On the name there are three explanations and no certainty: an old dialect word for marshes rich in water; a Latin personal name, perhaps Covanius or Aequanius, with the suffix that marks a property; or else, as the historian Giacomo Arditi held, simply guadagno, gain, for the fertility of the fields and pastures and for the lucrative activities carried on here. About the people of Guagnano, on the other hand, the neighbours have clear ideas, and have christened them twice. The first nickname is tuttu sensu, «all brains», and it comes from a story: a peasant of Guagnano, passing a field where men were labouring in vain to shift enormous boulders, told them that if they needed sense they could buy it in his village, where it cost little. The second is entri mueddrhi, «soft bellies», and it alludes to a certain preference for idleness and good living over work.
At the end of the thirteenth century Guagnano was a fief of the county of Lecce; then it passed to the Orsini del Balzo, princes of Taranto, and from there to a long file of families that closes with the Filomarini, dukes of Cutrofiano. In 1811 a large village was joined to it, Villa Baldassarri, which is still its only frazione; and until the thirteenth of April 1927 the comune belonged to the province of Brindisi. The countryside is dotted with farmsteads, some of them fortified, ranging from the thirteenth to the nineteenth century. The mother church, finished in 1798, wraps around a fifteenth-century building raised where an image of the Virgin of the Rosary had been found, and of that Virgin it keeps a fourteenth-century painting. On the edge of the village, finally, there is Vincent City: the house-museum that the artist Vincent Brunetti designed and built out of salvaged material, which has ended up in a documentary and in a music video, and which somebody comes to see every day.