question: What was the faction called that supported the Pope and the Holy Roman Emperor in the Italian city-states and that Alberico da Romano was a statesman of in the 1100's?
answer: The Guelphs and Ghibellines
context: Title: Treaty of Venice
  Passage: The Treaty or Peace of Venice, 1177, was a peace treaty between the papacy and its allies, the north Italian city-states of the Lombard League, and Frederick I, Holy Roman Emperor.  The Norman Kingdom of Sicily also took part in negotiations and the treaty thereby determined the political course of all Italy for the next several years.
  Title: Alberico da Barbiano
  Passage: Alberico da Barbiano (c. 1344–1409) was the first of the Italian condottieri.  His master in military matters was the English mercenary John Hawkwood, known in Italy as Giovanni Acuto.  Alberico's "compagnia" fought under the banner of Saint George, as the "compagnia San Giorgio".
  Title: Italian cruiser Alberico da Barbiano
  Passage: Alberico da Barbiano was an Italian "Giussano"-class light cruiser, that served in the Regia Marina during World War II.  She was named after Alberico da Barbiano, an Italian condottiero of the 14th century.
  Title: Alberico da Romano
  Passage: Alberico da Romano (1196 – 26 August 1260), called Alberico II, was an Italian condottiero, troubadour, and an alternatingly Guelph and Ghibelline statesman.  He was also a patron of Occitan literature.
  Title: List of Holy Roman Empresses
  Passage: Holy Roman Empress or Empress of the Holy Roman Empire is the title given to the consort (wife) or regent of the Holy Roman Emperor.  The elective dignity of Holy Roman Emperor was restricted to males only, therefore there was never a Holy Roman Empress regnant, though women such as Theophanu or Maria Theresa of Austria, who controlled the power of rule, served as de facto Empresses regnant.
  Title: Guelphs and Ghibellines
  Passage: The Guelphs and Ghibellines ( ; , also , ; Italian: "guelfi e ghibellini" ] ) were factions supporting the Pope and the Holy Roman Emperor, respectively, in the Italian city-states of central and northern Italy.  During the 12th and 13th centuries, rivalry between these two parties formed a particularly important aspect of the internal politics of medieval Italy.  The struggle for power between the Papacy and the Holy Roman Empire had arisen with the Investiture Controversy, which began in 1075 and ended with the Concordat of Worms in 1122.  The division between the Guelphs and Ghibellines in Italy, however, persisted until the 15th century.
  Title: Cunizza da Romano
  Passage: Cunizza da Romano (born c. 1198) was an Italian noblewoman, the third daughter of Ezzelino II da Romano and Adelaide di Mangona, and sister to Ezzelino III and Alberico da Romano.
  Title: Antipope Clement III
  Passage: Guibert or Wibert of Ravenna ( 1029 – 8 September 1100) was an Italian prelate, archbishop of Ravenna, who was elected pope in 1080 in opposition to Pope Gregory VII.  Gregory was the leader of the movement in the church which opposed the traditional claim of European monarchs to control ecclesiastical appointments, and this was opposed by supporters of monarchical rights led by the Holy Roman Emperor.  This led to the conflict known as the Investiture Controversy.  Gregory was felt by many to have gone too far when he excommunicated the Holy Roman Emperor Henry IV and supported a rival claimant as emperor, and in 1080 the pro-imperial Synod of Brixen pronounced that Gregory was deposed and replaced as pope by Guibert.
citations: Guelphs and Ghibellines Alberico da Romano