There were many imperial interregna in the history of the Holy Roman Empire, when there was no emperor. Interregna in which there was no emperor-elect (king of the Romans) were rarer. Among the longest periods without an emperor were between 924 and 962 (38 years), between 1250 and 1312 (62 years), and between 1378 and 1433 (55 years). The crisis of government of the Holy Roman Empire and the German kingdom thus lasted throughout the late medieval period, and ended only with the rise of the House of Habsburg on the eve of the German Reformation and the Renaissance. The term Great Interregnum is occasionally used for the period between 1250 (death of Frederick II) and 1273 (accession of Rudolf I).
After the deposition of Frederick II by Pope Innocent IV in 1245, Henry Raspe, Landgrave of Thuringia was set up as anti-king to Frederick's son Conrad IV (d. 1254). Frederick’s "deposition" was widely regarded as illegitimate, and no monarch in Europe offered any meaningful support for Innocent in his crusade against the emperor—whose immense status and legendary reputation as perhaps the greatest monarch of his day continued undiminished, especially in the vast Hohenstaufen core holdings. In Germany, particularly in Swabia, most of Franconia and the south, Hohenstaufen power remained formidable and the papal cause could only rely on the support of the major ecclesiastical princes. The secular princes of Germany were variably loyal to the Hohenstaufen or took a neutral stance. Henry Raspe was killed in 1247 and succeeded as anti-king by William of Holland (died 1256). Throughout 1249-1250 Conrad IV had steadily defeated William, whose power never extended beyond a tenuous hold north of the Rhine, and extracted a truce from the major ecclesiastical princes. Everywhere, papal crusade against the Hohenstaufen appeared to be disintegrating. By Frederick II’s death in late 1250, the emperor controlled most of Italy and his son enjoyed a relatively solid base across southern and central Germany. The Hohenstaufen remained the most prestigious, powerful and preeminent dynasty in Europe. However, buoyed by Frederick’s death, the papacy remained intransigent and Conrad IV was unable to secure the imperial mantle and died of malaria near Rome in 1254 while consolidating his Sicilian inheritance in southern Italy. Conrad’s death and the extreme youth of his son, Conradin, signaled an implosion in the Hohenstaufen dynastic power and after the 1257 imperial election, the crown was contested between Richard of Cornwall, who was supported by the Guelph party, and Alfonso X of Castile, who was recognized by the Hohenstaufen party but never set foot on German soil. After Richard's death in 1273, Rudolf I of Germany, a minor pro-Staufen count, was elected. He was the first of the Habsburgs to hold a royal title, but he was never crowned emperor. Alfonso hold on to his claim to the throne until 1275. After Rudolf's death in 1291, Adolf and Albert were two further weak kings who were never crowned emperor starting a line of so-called count-kings which lasted to the establishment of a de facto hereditary monarchy by the Habsburgs in the 15th century.