1. ITALY AT THE MERCY OF BARBARIANS AND THE BIRTH OF MONASTERYS  (V-VIII sec.)

After the fall of the Western Roman Empire (476 AD) several barbaric populations tried to settle themselves in the Italian peninsula. The Ostrogoths of Teodoric were sent away by the Byzantines (Greek-Gothic war), who however found a Territory torn by thirty years of war. Because of this scarce result it wasn't difficult for the Longbards (a population of Germanic origin) to penetrate in Italy (the penetration happened in 568, with king Alboino) and to conquer a great part of the peninsula, choosing Pavia as (the ancient Ticinum) as capital.

This climate of instability and of continuous wars put down the bases for a religious answer of an ascetic sent. Following the the oriental tradition, in fact, in Italy born the first monasteries, thanks to Benedetto from Norcia, who in 520 formed the monastery of Montecassino. But the famous rule of Benedictines "ora et labora" (pray and work) appeared in 540.
For centuries the monasteries remained the only cultural, social and economic centres.

2. THE FRANKS AND THE BIRTH OF THE PAPAL STATE  (VIII-IX sec.)

The Longbard domination lasted about two centuries, but it didn't manage to consolidate firmly its rule. Moreover the limit in the North began to be menaced by the growing power of Francs, who were enlarging their limits in all Europe, with Carolingian dynasty. Liutprando, a longbard king of VIII century, succeeded in tearing the Byzantine territories which separated the two longbard kingdoms and gave them to pontiff (Sutri and other territories). This was the beginning of the Church's temporal power, or the future State of the Church.
This donation caused however serious problems to the Longbards: the pontiff actually searched the Carolingian alliance, so Charlemagne descended in Italy and defeated the Longbards in 774.
The VIII century marked then a split of the peninsula; this split remained incurable (in spite of the different dominations): the North of Italy was dominated by the Francs, the Centre by the emergent  State of the Church, the South by the dukedom of Spoleto (a Longbardan domination) and by the Byzantines.

3. THE GERMAN EMPIRE AND THE '"ENCASTLEMENT" (X-XI sec.)

The Charlemagne's Empire was too large and heterogeneous, moreover, according to the Salic law of Francs, the kingdom had to be divided at king's death among his sons. So the enourmous empire of Charlemagne aplit into three (shared among the three sons: Ludovic, Lotario, Charles the Bald). Italy was annexed to Lotario's kingdom, which extended from Northern sea to the limit with Lazio.

From this split two different kingdoms had their origins: the The French Kingdom and the Teutonic empire (including the present Germany and Austria, and the regions of Italy mentioned).

In these century Europe, previously under the dominion of Charlemagne, underwent the invasions and the incursions of populations, which came from everywhere: in the North, the Normans attacked the France (and settled in Normandy), the populations who lived in Russia and, later, the south of Italy. In the East the Europe has been attacked by Slav populations and by the incursions of the Hungarians (or Magyar). At last the incursions of the Moors in the South; they attacckes above all the region on the Mediterranean and the monasteries in the hinterland (because of their riches).
The Europeans found the way to face these invasions and incursions through the centralisation of the inhabited territories into a castle or a defensive wall; this the phenomenon called "incastellamento".

4. THE FIGHT FOR INVESTITURE AND THE REIGN OF ITALY (X-XI sec.)

The temporal Kingdom of the Church achieved a great political imortance. The situation whichpermitted this reinforcement was question of the bishop's elections. The emblematic episode of this clash between Empire and Papacy, was  the excomunication of emperor Henry IV by the pontiff Gregory VII (Gregory fixed his power in his Dictatus Papae); so the emperor was forced to come to terms (at least in this occasion) in 1076-77 in Canossa.

The clash between Empire and Papacy would have involved the future italin cities. But there i another step to arrive at the birth of these indipendent kingdoms. Italian territory under the eperor's rules was becoming little by little autonomous; this was passible tanks to clever political manoeuvrings which conferre the dynastic succession for some important public offices. The leading characters of this emancipation from the empire were the dukes and the marquis of Spoleto, Tuscany, Ivrea, Friuli; they created that precarious identity so-called "Kingdom f Italy". 

5. THE ITALIAN COMMUNES, THE BIRTH OF UNIVERSITIES, THE REGIONAL STATES  (XI-XV sec.)

In questo periodo, a differenza delle altre regioni europee e del sud d'Italia in cui nacquero le monarchie, nell'Italia centro-settentionale si assiste alla nascita di poteri locali autonomi che passano sotto il titolo di "comuni".
La nascita di queste nuove realtà fu resa possibile: 
  a) dall'accentramento di poteri nelle mani dei vescovi locali, i quali erano eletti dai canonici della cattedrale e dai cittadini maggiorenti.
  b) dallo sviluppo economico basato, in un primo momento, sullo sfruttamento delle campagne.

La nascita dei comuni permise lo sviluppo di realtà commerciali nuove come le corporazioni: una divisione del lavoro (anche topografica, vedi ad es. la via dei lanaioli a Firenze) a seconda delle mansioni. Queste associazioni furono alla base del concetto di Universitas, che in quei tempi cominciò a significare anche la libera associazione di studenti e docenti, la prima delle quali fu quella di Bologna (1158).

Lo sviluppo dei comuni portò però ad un'ulteriore evoluzione: chi governava i comuni era, infatti, un podestà o capitano del popolo; tale carica fu resa ereditaria dai capitani più ambiziosi. 
Si crearono così concentrazioni di potere nelle mani di poche famiglie, generando quindi vere e proprie signorie.
Anche l'ordinamento territoriale fu modificato, col tempo i comuni che riuscirono ad accumulare una solida base economica e strategica ampliarono i loro confini trasformandosi in dominazioni regionali. 
Questo processo culminò con la pace di Lodi del 1454, che cercava di consolidare il risultato di questa espansione territoriale da parte dei comuni più potenti.