The white grape variety comes from Portugal. Synonyms (in bold the other main names) are Alva, Alva Branco, Alvadorão Alvadurão, Alvaro de Soire, Alvaro de Sousa, Boal Cachudo, Boal de Praga, Coda, Códega, Códiga, Codo, Codo ou Síria, Colhão de Gallo, Dona Branca, Dona Branca do Dão, Graciosa, Gracioso, Malvasia Branca, Malvasia Grosso, Posto Branco, Roupeiro, Roupeiro Chachudo, Roupeiro de Alcobaca, Sabro, Tamarez d'Algarve(Portugal); Blanca de Monterre, Blanca Extra, Blanco del País, Chelva Blanca, Cigüente, Ciguentes, Crato Branco, Doña Blanca, Malvasia, Malvasia Blanca, Malvasía Castellana, Malvasía Grossa, Moza Fresca, Valenciana, Verdegudillo (Spain).
Despite the apparent synonyms or morphological similarities, it should not be confused with the varieties Côdega de Larinho, Dona Branca, Jampal, Malvasia Fina, Roupeiro Branco or Tamarez. According to DNA analyses carried out in 2012, a parent-offspring relationship exists between Cayetana Blanca and Síria. A further analysis in 2013 showed that Síria is the result of a presumably natural cross between Hebén x unknown partner. However, this is based on only 20 DNA markers (see molecular genetics). A cross between Malvasia Fina x Síria resulted in the variety Ratinho.
It was first mentioned under the name Cigüente in 1513 in Spain by the agronomist Gabriel Alonso de Herrera (1470-1539) and in Portugal under the name Alvaro de Sousa in 1531. The exact origin of the variety is probably to be found in the area around the municipality of Pinhel in the north-east of Portugal. The late ripening, high-yielding vine is susceptible to both mildew and botrytis. It produces white wines with moderate acidity and alcohol content and a wide range of aromas of lime, acacia, orange and laurel, which tend to oxidise. The variety is also used as a table grape.
The variety is widespread in Portugal from the Douro and Beiras areas in the north to Alentejo and Algarve in the south. The total area under cultivation here is 7,145 hectares. In Spain it is mainly grown in Galicia and Extremadura. A total of 753 hectares have been designated here. In 2010, the variety occupied a total of 7,898 hectares of vineyards, with an extremely upward trend (ten years earlier it was 2,791 hectares). It was ranked 87th in the worldwide grape variety ranking (Kym Anderson).