The most ambitious of all Almohad buildings, the Hassan Mosque was, in its time, the second largest mosque in the Islamic world, outflanked only by the one in Smarra, Iraq. Though little remains today apart from its vast tower, or minaret, its sheer size still seems a novelty.
The mosque was begun in 1195 – the same period as Marrakesh’s Koutoubia and Seville’s Giralda – and was designed to be the centrepiece of Yacoub el Mansour’s new capital in celebration of his victory over the Spanish Christians at Alarcos, but construction seems to have been abandoned on El Mansour’s death in 1199. Its extent must always have seemed an elaborate folly – Morocco’s most important mosque, the Kairaouine in Fez, is less than half the Hassan’s size, but served a much greater population. Rabat would have needed a population of well over 100,000 to make adequate use of the Hassan’s capacity, but the city never really took off under the later Almohads and Merenids; when Leo Africanus came here in 1600, he found no more than a hundred households, gathered for security within the kasbah.
The mosque’s hall, roofed in cedar, was used until the Great Earthquake of 1755 (which destroyed central Lisbon) brought down its central columns. Never rebuilt, some of the columns have been partially restored and at least offer some sense of the building’s size. The imposing tower has remained standing, and dominates almost every view of the capital. It is unusually positioned at the centre rather than the northern corner of the rear of the mosque. Some 50m tall in its present state, it would probably have been around 80m if finished to normal proportions – a third again of the height of Marrakesh’s Koutoubia. Despite its apparent simplicity, it is arguably the most complex of all Almohad structures. Each facade is different, with a distinct combination of patterning, yet the whole intricacy of blind arcades and interlacing curves is based on just two formal designs. On the south and west faces these are the same darj w ktaf motifs as on Bab Oudaïa; on the north and east is the shabka (net) motif, an extremely popular form adapted by the Almohads from the lobed arches of the Cordoba Grand Mosque – and still in contemporary use.