Ulric, marquis or vice-marquis of Tuscany and imperial vicar, commanded the Florentine army, with which he advanced to the gates of Siena and burned a suburb; the Sienese demanded assistance from Lucca, who answered by declaring war on Florence, not only to draw the enemy from her ally, but also in aid of Count Guido Guerra of Modigliana, a Ghibelline chief and confederate of Siena, who had already suffered from Florentine aggression. Pisa on the other hand took the field at the request of the Florentines and Count Guido’s possessions were devastated by these combined forces while the Sienese, covertly advancing on Florence, fell into an ambuscade and were nearly all made prisoners. More bitter was the struggle between Pisa and Lucca where no exchange of prisoners took place, no ransom was accepted, and where a strong personal feeling of hatred pervaded every class; perpetual incarceration was with them the consequence of defeat, and we are told by the bishop of Fresingen that several years afterwards he saw “the Lucchese officers, wasted, squalid, and miserable, in the dungeons of Pisa, drawing tears of compassion from every passing stranger.” At this period, however, not Tuscany alone but all northern Italy seems to have been in similar confusion from similar causes; from jealousy, faction, and that ever boisterous passage between comparative bondage and complete independence, for Conrad with full employment in Germany was forced to leave Italy uncontrolled, a prey to angry passions, unsettled institutions, and political anarchy. The particular causes of discord between the Tuscan cities are now difficult to trace; vicinity, by multiplying the points of contact, increased the chances and was always a source of dissension; but the peculiar enmity between Siena and Florence, according to the Sienese historians, originated in the assistance given to Henry IV during the siege of 1081; an injury in itself not easily forgiven, but which, fostered as it was by national emulation, lasted until long after the ruin of both republics. [Sidenote: [1146-1204 A.D.]] Elated by success and jealous of the counts Guidi by whose possessions she was nearly surrounded, Florence assembled an army in February, 1146, and besieged Monte Croce, a _castello_ about nine miles distant which belonged to that family; but confidence in superiority of force created carelessness of conduct, and Count Guido aided by the people of Arezzo defeated them with great loss. For a time they were quieted by this sharp military lesson, and a crusade the following year under the emperor Conrad III carried off some of their more enterprising and devout spirits to Palestine; amongst them Dante’s ancestor Cacciaguida, who, after having been knighted by Conrad, fell in battle against the infidels.[e]