It's probably the most famous island of the venetian Lagoon, it's composed by seven minor islands. It is well known worldwide for the art of blowing glass. All glass factories were moved to the island of Murano in 1295 to preserve the city from fires that often were caused by factories themselves.
Murano was at first inhabited by refugees coming from Altino right after the barbarian invasion. Today it is completely urbanized and counts on 5500 inhabitant. Until 1171, when it was annexed to the Santa Croce district, the island was autonomous. In the year 1275 part of the autonomy was returned to the island's government, so they could promulgate laws and even coin their own money (the Osella). The autonomy of Murano was maintained also during the Austrian domination, that made of it a municipality. During the Austrian occupancy many churches and monasteries were sacked and destroyed so that only three now are left. The Murano municipality (that includes San’t Erasmo and Vignole islands) was suppressed in 1923 and the territory unified with the Municipality of Venice.
http://venice-tourism.com/en/luoghi/island-lagoon/murano-island