This village changed its name because its castle ate it. The first place name appears in a deed of sale of 958, preserved in the abbey of Cava de' Tirreni, which speaks of land in locum ziziro; the root Ziz is Arabic and means splendid, pleasant — the same that lies in the Zisa of Palermo — and takes us back to the time of the emirate of Bari, when the Saracens held the city and a good twenty-odd strongholds all around it. In 1077 the place is still called Siziro. Then the Normans arrive, at the end of the eleventh century: they find the remains of an older castle structure — a quadrilateral with four round corner towers, and nobody can say who built it — they raise it again reusing its stones, and Umfredo and Guglielmo d'Altavilla christen it San Nicandro, as was their habit, because they came from San Nicandro di Sicignano degli Alburni. The name belonged to the stronghold, not to the village; but in the bishop's documents of 1172 Siziro no longer appears, and only San Nicandro is written. The castle had taken the village too. The addition «di Bari» dates instead from 1863.
A great deal is known about that castle because the charters tell it. In 1119 Emma d'Altavilla, then at Santa Severina, donated the tithes of the fief to the abbot of Montescaglioso on one condition: that he send a chaplain to say mass in the chapel of San Nicola recently built inside the walls. A document of 1146 describes the site as it was: the castle now has eight towers, an irregular quadrilateral curtain and a moat, the chapel inside, and the village all around it. At the beginning of the thirteenth century it is enlarged again, with a new palace, stables, warehouses, another moat and new gateways, because the fief was rich in grain and livestock and lay on the shortest road between Bari and Matera: the castle became a grange, that is, a store supplying the Crusaders overseas. The epic over, on the first of November 1304 king Charles II gave it entirely to the basilica of San Nicola at Bari. In the excavations Byzantine coins have come to light and a gold tarì with a legend in Kufic characters. The philosopher Domenico Losurdo was born here.