There is evidence of a limited cultural borrowing from the Mozarabs by the Muslim community in Al-Andalus. For instance, the Muslims' adoption of the Christian solar calendar and holidays was an exclusively Andalusi phenomenon. In Al-Andalus, the Islamic lunar calendar was supplemented by the local solar calendar, which were more useful for agricultural and navigational purposes. Like the local Mozarabs, the Muslims of Al-Andalus were notoriously heavy drinkers. Muslims also celebrated traditional Christian holidays sometimes with the sponsorship of their leaders, despite the fact that such fraternisation was generally opposed by the Ulema. The Muslims also hedged their metaphysical bets through the use of Roman Catholic sacraments.