Serra Bas

The Serra Bas, also called the De Serra-Bas or House of Bas, ruled the Judicate of Arborea, a Sardinian judge-kingdom with its capital at Oristano. The line emerged from the House of Cervera after the Treaty of Oristano of 1192, and judges such as Marianus II reunited the realm and briefly held most of Sardinia.

Hugh II allied with Aragon in the 1320s, but his son Marianus IV turned against the Aragonese and conquered almost the whole island. After Hugh III died without heirs in 1383, Marianus's daughter Eleanor became regent for her young sons, upheld the revolt and gave Arborea the Carta de Logu.

The dynasty's fortunes collapsed after the Aragonese victory at Sanluri in 1409 and the fall of Oristano in 1410. Alfonso V of Aragon bought out the rival Narbonne claim in 1420, opening the way to the conquest of Sardinia.