The basis of the monetary system was that of the Roman Empire (denarii, solidi, librae). The coinage of this period consist exclusively of solidi and tremisses. Fractions of the solidus known as "semissis" (half-solidi) and "tremissis" (one-third solidi) were also produced. The late soldier's disposable income would thus have averaged at least 2 "solidi" per annum. In 583, the Avars demanded an increase in the tribute to 100,000 solidi. The final cost amounted to 26,000 "solidi" (gold pieces). After the capture of Sirmium, the Avars demanded 100,000 solidi a year. The Syracuse "solidi" were generally lighter (about 3.8g) and only 19k fine (79% pure). In 2011, a 30 solidi coin was issued to commemorate the 30th anniversary of Atlantium. If someone abducted another person's maidservant, the abductor would be fined 30 solidi. These reduced solidi, with a star both on obverse and reverse, weighed about 4.25 g.