Porta Saragozza could be called the “Holy Gate” or the “Gate of Pilgrims” (“Porta sacra”, “Porta dei pellegrini”) for two reasons: first – its name should remind of the mythical victory of Christians against Muslims in a faraway Iberian land; second – the gate has been an important point on the way to the hill Colle della Guardia and to the Sanctuary of Beata Vergine di San Luca (Virgin Mary of San Luca) – the goal of many processions and pilgrims. The gate was built in the 13th century, an avant-corps and a drawbridge over the moat were added in 1334. The present look is the result of the restoration carried out by Giuseppe Mengoni in 1859 who replaced the medieval keep and joined it to two cylindrical towers with the “portico” decorated by merlons. During first centuries of its existence, the gate had a secondary importance and it was closed for several times (the gate is not mentioned in the Descriptio from 1371). The gate became important after the building of the “portico” (arcades) leading to the Sanctuary of Virgin Mary of San Luca in 1674. Processions that previously were passing through the Sant'Isaia gate, took as a starting point the Saragozza gate.
Source: "Restauro delle porte di Bologna 2007-2009"