One of the most serious eruptions of Mount Etna happened in 121 BC, when a great part of Catania was overwhelmed by streams of lava, and the hot ashes fell in such quantities in the city itself, as to break in the roofs of the houses. Catana was in consequence exempted, for 10 years, from its usual contributions to the Roman state. The greater part of the broad tract of plain to the southwest of Catana (now called the "Piana di Catania", a district of great fertility), appears to have belonged, in ancient times, to Leontini or Centuripa (modern Centuripe), but that portion of it between Catana itself and the mouth of the Symaethus was annexed to Catana and must have furnished abundant supplies of grain.