Ancient origins of Pisa
The origins of Pisa are rather uncertain - there are some hypotheses about a possible Ligurian or Greek origin, and we have evidence of an Etruscan settlement dating from the 6th century. In the 4th century Servius  attested that, according to Cato (234-149 BC):
“Pisas tenuerint ante adventum Etruscorum, negat sibi compertum* ” [Cato did not know who had ruled Pisa before the arrival of the Etruscans]. Cato says explicitly that Pisa was founded by the Etruscans and relegates the Greek presence to a vague area, with an equally vague population that he refers to as "talking Greek".
* The expression "negat sibi compertum” indicates that his searches for information have failed, that is, that Cato was not able to find reliable data in written and in oral sources.
Later Pisa was also a Roman colony, with a port that was often used as a military base for the Roman fleet. Pisa became a municipium in 86 BC. and a colony called “Opsequens Iulia” in the Augustan age.
An example of a remnant from Pisa in Roman times is the so-called "Nero Baths" (late first century AD) with an octagonal room inside for hot air baths, located in an area called "Parlascio". The excavations in “Piazza dei Miracoli” have brought to light part of a neighborhood of a private domus, abandoned in the 4th and 5th centuries AD.
The study of ancient Pisa is particularly complex because of the intensive medieval and post-medieval construction. Historic sources define Roman Pisa as having been a city full of temples, public baths and shops.
Pisa after the Romans
Pisa was subsequently ruled by the Byzantines and the Lombards. The written sources are silent about the manner and even the history of the fall of Pisa in the hands of the Lombards which is traditionally dated to 643, the year of the Rotari’s [606-652] conquest.
Archaeological data is available from the first half of the 7th century, concerning burials and found in the Piazza del Duomo, with finds such as glass beads and coins.
Pisa from the Middle Ages
In the Middle Ages Pisa became one of the four most powerful Maritime Republics alongside Venice, Amalfi and Genoa; in this period, the city ensured the domination of the western Mediterranean.
Between the 12th and 14th century Pisa, thanks to its strategic and military importance, was enlarged by incorporating several villages that arose around it. This led to the creation of new streets and squares, and especially the typical "case-torri" [Tower Houses], belonging to the nobility and the wealthy merchant class of the city, who ensured a large urban and economic development for Pisa.
The growth of the city stopped when Pisa was conquered by the powerful Florence, which ruled it between 1405 and 1494. However, under the rule of Florence, Pisa was greatly fortified towards the sea, with masonry work including the activities of famous military engineers such as Filippo Brunelleschi (1337-1446), designer of the dome on the duomo in Florence.
In 1494 Charles VIII of France (1470-1498) saved Pisa from its dominion by Florence and restored its independence, which lasted until 1509, when it came again under the dominion of Florence, who entrusted Antonio da Sangallo (1484-1546) with the task of rebuilding the fortifications of the city, destroyed during previous wars.
Under the rule of Cosimo I (1519-1574), Pisa was again reinforced. However, according to documents dating from the 18th century, the city was now in decline.
Pisa was reconstituted under the Grand Duke Peter Leopold of Habsburg-Lorraine (1747-1792), who modernized the road infrastructure and many buildings. In the 19th century, Pisa had its city plan changed by the creation of important works such as the Piazza Vittorio Emanuele .
Origins of the name Pisa
Significant doubts also remain today about the etymology of "Pisa." On the complex problem of the origins of Pisa and its name there have been various hypotheses by Pliny (23-79 AD), Cato, Dionysius of Halicarnassus (60-7 BC), Trogus [1st century BC], Fazio degli Uberti (1309-1367), Leandro Alberti (1470-1552), and Cristoforo di Forlì [died 1528], according to whom Pisa derived its name from “Pisa”, the city of Arcadia in the Peloponnese.
According to G. Benvenuti the origin of the name is often considered to date from the Greeks or the Etruscans, however, it is now generally accepted that the etymology of Pisa means "marshy place":
"Maybe Eusebius Pamphilus (died 340) was not far from the truth, who wrote that 'Pisos' meant 'marshy place'" .
See the Pisa guide if visiting the town.
1. Aen. x, 179
2. See G. Benvenuti, “Storia della Repubblica di Pisa...”, 1961, Vol. I, p. 22
3. On these issues, See O. Niglio, “Tesori militari e ipotesi di trasformazione nel nuovo assetto urbano della città si Pisa”, in “Città e Storia”, IV, 2009, 2, pp. 417 ff.