Valença's fortaleza is in fact two fortresses, bristling with bastions, watchtowers, massive gateways and defensive bulwarks, connected by a single bridge. The old churches and Manueline mansions inside testify to the success of the fortifications against several sieges, some as late as the 19th century. The earliest fortifications date from the 13th-century reign of Dom Afonso III, although largely what you see today was built in the 17th century, its design inspired by the French military architect Vauban.
Zip past the tacky gift shops and towel merchants and follow the cobbled lanes to the far end of the larger northern fortress, which incorporates Dom Afonso’s original stronghold and contains almost everything else that’s of interest. From Praça da República bear right, then left, into Rua Guilherme José da Silva (which turns into Rua Dr Pedro Augusto Dias). On the left, opposite the post office, is the Casa da Eira, with a handsome Manueline window somewhat marred by a horrendous corrugated tin roof that peeks above the crenellated walls. The 14th-century Igreja de Santo Estevão, with its neoclassical facade, is at the end of the street. From the church, take a left and you'll see the 1st-century Roman milestone from the old Braga–Astorga road.
From the milestone continue north to the end of Rua José Rodrigues and the now-decrepit Romanesque parish church, Igreja de Santa Maria dos Anjos, dating from 1276. At the back is a tiny chapel with Romano-Gothic inscriptions on the outside. To the left of the parish church is the Capela da Misericórdia and beyond it the Pousada de São Teotónio.
But the best fun can be had rambling on and around the series of exterior walls. In fact, if you turn right by the pousada you’ll descend the atmospheric lane through one of the original gates, with a trickling stream running below and an impressive echo. Keep going and you’ll pass through several thick, mossy layers to the outside world.