rather than "basilissa" (βασίλισσα), 'empress', in fact there are only three instances where it can be proven that she used the title "basileus": two legal documents in which she signed herself as "Emperor of the Romans" and a gold coin of hers found in Sicily bearing the title of "basileus". In relation to the coin, the lettering is of poor quality and the attribution to Irene may be problematic. She used the title "basilissa" in all other documents, coins, and seals. Carolingian Empire Irene's unprecedented position as an empress ruling in her own right was emphasized by the coincidental rise of the Carolingian Empire in Western Europe, which rivaled Irene's Byzantium in size and power. Charlemagne invaded Italy early on in his reign, annexing the Lombard kingdom of Italy. He also campaigned against the Saxon tribes in northern Germany for more than thirty years, annexing their territory and compelling them to convert to Christianity, and defeated the Avars in Central Europe. In the Iberian Peninsula, Charlemagne's expedition against al-Andalus led to the creation of a buffer zone between Francia and the Islamic world called the Spanish Marches. Charlemagne also increasingly modelled his rule after that of the Roman emperors by sponsoring enormous construction programs, exemplified by the building of his favourite residence at Aachen (in modern-day Germany), standardizing weights and measures and supporting intellectual and artistic endeavors in the Carolingian renaissance. Charlemagne was crowned Emperor by Pope Leo III on Christmas Day, 800. The clergy and nobles attending the ceremony proclaimed Charlemagne as "Augustus". In support of Charlemagne's coronation, some argued that the imperial position was actually vacant, deeming a woman unfit to be emperor; however, Charlemagne made no claim to the Eastern Roman Empire. Whether he actually desired a coronation at all, remains controversial – his biographer Einhard related that Charlemagne had been surprised by the Pope – but the Eastern Empire felt its role as the sole Roman Empire threatened and began to emphasize its superiority and its Roman identity. Relations between the two empires remained difficult. Irene is said to have endeavored to bring about a marriage alliance between herself and Charlemagne, but according to Theophanes the Confessor, who alone mentions it, the scheme was frustrated by Aetios, one of her favorites. Deposition and death In 802 the patricians conspired against her, deposing her on 31 October, and placing Nikephoros, the minister of finance (logothetēs tou genikou),