This thesis contrasts with the fact that the oldest inhabited area, like most of the towns of Valpolcevera, rose further upstream, sheltered from the torrent's floods.
The main centers (Rivarolo, Certosa and Teglia) are located on the left of the stream, aligned along the former Strada Statale 35 dei Giovi.
At that time around the church and along the road that from Begato descended to the fords of the stream in the direction of Fegino and the Genoese west, the village of Costa, also known as Rivarolo Soprano, was formed.
In the Middle Ages the Fieschis, lords of the area, had a palace built there and, on the Pigna hill, a castle, which was destroyed during the clashes that took place in 1325 between Guelphs and Ghibellines.
[4] Along the direct road to Begato, on the hill above the church, in 1612, in a land purchased by the Spinola family, the Franciscan friars would have built the convent of N.S.
The subsequent renovation and expansion works of the hospital no longer allow us to recognize the original structure of the building, with the exception of the adjoining chapel.
In the meantime, towards the end of the thirteenth century, the Carthusian monks had settled with another grandiose monastery in Rivarolo Sottano, a place that would later take the name of Certosa from them.
In the first months of 1747 the Austrians, expelled from Genoa in December 1746 following the revolt that began with the legendary episode of the Balilla, occupied the surroundings from where they laid siege to the city in an attempt to recapture it.
The historical nucleus of that period, still easily recognizable, despite the impetuous building development of the twentieth century, consists of the village, crossed by the current Via Celesia, located between the left bank of the Polcevera stream (whose bed, before the construction of the embankment in the mid-nineteenth century, it was much wider than the current one) and the overlying hill, with the church of the Assumption and the convent of NS of Mercy.
Between the lower and upper Rivarolo the Turbella stream passes, which descends from the mountain of the due Fratelli; it helps to fertilize the countryside of this district capital; which, if it does not produce a large quantity of cereals, provides many good fruits, and so much hay that it can keep many cattle, horses, mules, donkeys, and even sheep and goats, of which the products are remarkable.Towards the middle of the nineteenth century, with the embankment of the river and the construction of the railway, the industrial development of Valpolcevera began, which also led to a great demographic, urban and road development.
The 1920s saw the urban and residential development towards the hill of Misericordia, favored by the opening, in 1923, of the carriage road to the Celesia hospital (via P. Negrotto Cambiaso).