In southwest Asia the first streets of 8th century Baghdad were paved with tar, derived from natural seep fields in the region. In the 9th century, oil fields were exploited in the area around modern Baku, Azerbaijan. These fields were described by the Arab geographer Abu al-Hasan 'Alī al-Mas'ūdī in the 10th century, and by Marco Polo in the 13th century, who described the output of those wells as hundreds of shiploads. Distillation of petroleum was described by the Persian alchemist, Muhammad ibn Zakarīya Rāzi (Rhazes). There was production of chemicals such as kerosene in the alembic ("al-ambiq"), which was mainly used for kerosene lamps. Arab and Persian chemists also distilled crude oil in order to produce flammable products for military purposes. Through Islamic Spain, distillation became available in Western Europe by the 12th century. It has also been present in Romania since the 13th century, being recorded as păcură.