Atop this granite peak stand Pedras Alvas. These aren’t just any stones. They mark a precise point a geodetic survey point. Pedras Alvas is a third-order geodetic vertex.
For centuries this spot has witnessed history unfold below. Imagine the ancient Callaeci the Celtic people who first settled here. They built a castro a fortified village. Its walls stood against the elements and invaders. The remains are partially visible.
Then came the Romans. They conquered this land. They built their own fortifications expanding the settlement near the Douro River. They called it Portus Cale. Its location may have been near here. This name evolved over time becoming Portugal. The name Pedras Alvas itself is much younger.
The Suebi and Visigoths controlled this region later. The Parochiale Suevorum a manuscript describing the Suebi’s church organization mentions two Portucales one older and Roman on the left bank of the Douro and a newer one founded by the Suevi on the right bank. The location of the older Portus Cale is still debated. It could have been this very area.
Archaeological excavations near Pedras Alvas since the 1980s offer proof. They show settlements dating back to the Iron Age. They also reveal Roman structures and evidence of pre-medieval fortifications. The remains found include granite blocks. These blocks demonstrate the strength and skill of the builders.
Later medieval walls were built as well. The Fernandina walls are more famous. They encircle a larger area of Porto. The original walls were possibly smaller perhaps centered on the hill where Pedras Alvas stands. They were repaired and rebuilt multiple times over centuries.
Today Pedras Alvas stands as a silent witness. It is a reminder of layers of history. It is a tribute to those who lived and worked here. Its precise location is a treasure for surveyors and historians. It is a piece of Porto’s fascinating and complex past. The views from Pedras Alvas are breathtaking. They stretch over the city of Porto and the Douro River.