From Piazza Mercato delle Scarpe, Via Gombito leads up to Piazza Vecchia , enclosed by a harmonious miscellany of buildings, ranging from wrought-iron-balconied houses containing cafés and restaurants to the opulent Palladian-style civic library. Stendhal rather enthusiastically dubbed the square “the most beautiful place on earth”, and certainly it’s a striking open space, the most imposing building the medieval Palazzo della Ragione , a Venetian-Gothic-style structure that stretches right crossways the piazza, lending a stagey feel to things, especially at night when the wrought-iron lamps are switched on. Court cases used to be heard under the open arcades that form the ground floor, and, following a guilty verdict, condemned criminals were exhibited there. The piazza itself was the scene of more joyous celebrations in 1797, when the French formed the Republic of Bergamo. A “tree of liberty” was erected, and the square, carpeted with tapestries, was transformed into an open-air ballroom in which – as a symbol of the new democracy – dances were led by an aristocrat partnered by a butcher. To the right of the Palazzo della Ragione is the entrance to the massive Torre Civica , or Torre del Campanone, which you can ascend by lift (May to mid-Sept regular 10am-8pm, Fri & Sat until 10pm; mid-Sept to Oct Mon-Fri 9.30am-12.30pm & 2-7pm, Sat & Sun 10am-7pm; Nov-Feb Sat & Sun 10.30am-12.30pm & 2-6pm; March & April Wed-Sun 10.30am-12.30pm & 2-8pm; L2000/¬1.03). Its fifteenth-century bell, which narrowly escaped being melted down by the Germans to make arms during World War II, still tolls every half-hour. Afterwards, achievement through the palazzo’s arcades to the Piazza del Duomo and the Duomo on the left – though this is of less interest than the church of Santa Maria Maggiore in front, a rambling Romanesque church garnished with a scalloped Gothic porch crowned by two loggias sheltering statues of saints. Inside, Santa Maria is an extraordinarily elaborate church, its ceiling marzipanned with ornament in the worst tradition of Baroque excess, encrusted with gilded stucco, painted vignettes and languishing statues. There’s a piece of nineteenth-century kitsch too – a monument to Donizetti, the Bergamo-based composer of highly favourite romantic comedies with memorable melodies and predictable plots who died from syphilis here in 1848. As the town’s most famous son, his death was much grieved, and bas-relief putti stamp their feet and smash their lyres in misery over the event. More subtly, the intarsia biblical scenes on the choir stalls – designed by Lotto, and executed by a local craftsman – are remarkable not only for their intricacy but for the incredible colour-range of the natural wood.

Even the glitziness of Santa Maria is overshadowed by the Renaissance decoration of the Cappella Colleoni next door (April-Oct regular 9am-12.30pm & 2-6.30pm; Nov-March Tues-Sun 9am-12.30pm & 2-4.30pm). Built onto the church in the 1470s, the chapel is a gorgeously extravagant confection of pastel-coloured marble carved into an abundance of miniature arcades, balustrades and twisted columns, and capped with a mosque-like dome. Commissioned by Bartolomeo Colleoni, a Bergamo mercenary in the pay of Venice, it was designed by the Pavian sculptor Amadeo – responsible for the equally excessive Certosa di Pavia. The interior is almost as opulent, with a ceiling frescoed in the eighteenth century by Tiepolo sheltering Colleoni’s sarcophagus, encrusted with reliefs and statuettes, and topped with a gleaming gilded equestrian statue. There’s also the more modest tomb of his daughter, Medea, who died aged 15. Note Colleoni’s coat-of-arms on the gate as you enter, the smoothness of the third “testicle” (supposedly biologically true) bears witness to the local tradition that rubbing it will bring you luck.

Take a look, too, at the nearby Baptistry (visits by appointment, tel 035.210.223), removed from the interior of Santa Maria Maggiore in the seventeenth century when christenings were transferred to the duomo. After some time in storage it was eventually reconstructed outside the Aula della Curia (”Bishop’s Court”; Mon-Fri 9am-12.30pm; free), alongside the Cappella Colleoni, which contains thirteenth- and fourteenth-century frescoes of the life of Christ, including an odd scene in which Christ judges the damned, holding a dagger, Damocles-like, in his teeth. Behind, at the back of Santa Maria Maggiore, is the bulging and recently restored, although still closed to the public, Tempietto di Santa Croce , dating from the tenth century.

Leading out of Piazza Vecchia, Via Colleoni also memorializes Bartolomeo Colleoni; it’s a narrow street but one of the upper city’s main pedestrian thoroughfares, leading to the brink of Bergamo Alta and lined with pastry shops selling chocolate and marzipan cakes topped with birds ( uccelli ). Luogo Pio Colleoni , Via Colleoni 9-11 (May-July Sun 10am-1pm & 2-7pm; L1500/¬0.78), was Colleoni’s Bergamo residence; it was also the headquarters of a charitable institution that he set up to wage dowries for poor women – the Venetians ruled that no woman could marry without one. Only two rooms of the original house still exist. The first displays the original Amadeo statues from the front of the Cappella Colleoni and some average frescoes depicting Colleoni; the second was once the meeting room for the charity’s council members, who these days continue a modernized version of their good work from upstairs, giving financial aid and lodgings to widows. Also upstairs, there’s a small museum (visits by appointment only, tel 035.218.568) containing copies of Colleoni’s arms; the originals were found when his tomb was opened. At the end of Via Colleoni, Piazza Mascheroni lies at the entrance to the Cittadella , a military stronghold built by Barnabo Visconti that originally occupied the entire western headland. The remaining buildings now house a small theatre and two museums : one of archeology (Tues-Sun 9am-12.30pm & 2.30-6pm; free) and the other of natural history (Tues-Fri 9am-12.30pm & 2.30-6pm, Sat & Sun 9am-7.30pm; free).

There are good views from here crossways the Colle Aperto (Open Hill) to Bergamo Bassa, though for really outstanding views you need to achievement up to the Castello , perched on the summit of San Vigilio, which rises up from Porta Sant’Alessandro. A funicular operates in summer but the achievement is pleasant, up a steep narrow road overlooking the gardens of Bergamo’s most desirable properties, and past very captivating but rather pricey bars and restaurants. In the grounds of the castle there’s a maze of underground passages to explore that used to run right down to Bergamo Alta. If you’re interested in the subterranean world, there are guided tours of the tunnels under the Venetian surround (the surround that encloses Bergamo Alta) organized by the Gruppo Speleologico Le Nottole (tel 035.251.233; hours and price vary according to season and size of group).

Returning to the Colle Aperto, you can either achievement back through the city or follow the old walls around its circumference – the whole circuit takes a couple of hours. The most picturesque stretch is between the Colle Aperto and Porta San Giacomo, from where a long flight of steps leads down into the lower city. Alternatively, returning through the upper city to Piazza Mercato delle Scarpe, you can turn down Via San Pancrazio and then into Piazza Mercato del Fieno, to see the Museo Storico (Tues-Sun 9.30am-4pm; free). Housed in the ex-convent of San Francesco, it currently spans the history of the city during the Unification and is relatively small, but there are plans to display the rest of the collection, which covers the last hundred years, as and when funds allow. Heading easterly from here you’ll climb to Via Rocca, which leads up to the grounds of the Rocca , where there is little to attract your attention, apart from a view over orient Bergamo, before you delve into the twisting streets of the medieval quarter below.