When Nicola Romeo bought ALFA in 1915, his surname was appended to the company name.
The company's first automobile was the 24 HP  (http://members.tripod.lycos.nl/AlfaTom2/galleria1/24hp.htm), which appeared in 1910, and the following year entered the Targa Florio[?], the special competition in Sicily.
In the 1930s, Tazio Nuvolari won the Mille Miglia[?] in a 6C 1750  (http://members.tripod.lycos.nl/AlfaTom2/galleria1/24hp.htm), crossing the finishing line after having incredibly overtaken Achille Varzi[?] without his lights (at nightime).
In 1950 Nino Farina[?] won the Formula One World Championship in a 158 with compressor, in 1951 Juan Manuel Fangio won while driving a Alfetta[?] 159 (first attempt of two-stages compressor). Other titles won in 1975 and 1977, while the 33 dominated the Prototype category from 1967 to 1977.
In the 1960s Alfa Romeo was bought by the Italian government and became famous for its models specifically designed for Italian police ("Panthers"  (http://www.poliziadistato.it/pds/chisiamo/storia/pantere/scheda3.htm),  (http://www.poliziadistato.it/pds/chisiamo/storia/pantere/scheda2.htm),  (http://www.poliziadistato.it/pds/chisiamo/storia/pantere/scheda9.htm),  (http://www.poliziadistato.it/pds/chisiamo/storia/pantere/scheda5.htm),  (http://members.tripod.lycos.nl/AlfaTom/polizia/155pol2.jpg)) and Carabinieri ( (http://members.tripod.lycos.nl/AlfaTom/polizia/156carab1.jpg)); among them the glorious "Giulia Super"  (http://www.alfaclubdc.com/sprbrch1.gif) -  (http://members.tripod.lycos.nl/AlfaTom/berlinas/giuliaberlina.htm) -  (http://www.alfaromeo-classic.com/giulia/super_schaer/Bilder/giulia_super.1.jpg), first car with double volumetric compressor to be used on normal traffic. Or the 2600 Sprint GT  (http://members.tripod.lycos.nl/AlfaTom/2600sprint.htm), which obtained an expressive nickname of "Inseguimento" (this car is wrongly supposed to be the one that the famous Roman police marshall and unrivalled driver Armandino Spadafora brought down on the Spanish Steps while following some robbers - it was instead a black Ferrari GT 50 - this pic of Giulia  (http://www.alfaclubdc.com/suprflm3.jpg), one of the dozens about this legend, is taken from a movie and not at Spanish Steps).
At the end of the 1970s, a general economical crisis caused the government to sell Alfa Romeo to Fiat, which still owns it.
Before being bought by Fiat, Alfa Romeo always had a daring commercial policy, constantly experimenting with new solutions and using them in its series production  (http://members.tripod.lycos.nl/AlfaTom2/galleria1/8c2900blungo.htm), even at the risk of losing market share  (http://members.tripod.lycos.nl/AlfaTom2/galleria1/6c2500vde.htm),  (http://members.tripod.lycos.nl/AlfaTom/prototipo/canguro.htm),  (http://members.tripod.lycos.nl/AlfaTom/prototipo/carabo.htm). On an English sales brochure:
It represented the make of those cars which could allow some sport driving on common roads, provided the driver was clever enough to let them express their particular "sound".
Owners of an A.R. call themselves "Alfista", in Italian. Alfa Romeo is sometimes worshipped by its owners, and many models have become cultural symbols  (http://www.alfaromeo-classic.com/occ/alfetta/Bilder/alfetta1.jpg). In 1967 the famous Dustin Hoffman's film "The Graduate" gave worldwide unforgettable celebrity to the "Spider" (best known with the Italian nickname of "Duetto", or as "Osso di Seppia" or Round-tail), and its unique shape. See here  (http://home.wanadoo.nl/thomas-j.visser/galleria2/duetto.htm) -  (http://hem.passagen.se/veloce/wpe28.jpg). The Spider was designed by Pininfarina.
Alfa Romeo's typical color is red. Until the 1980s, Alfa Romeos, except for the Alfasud, were rear-wheel-drive. Since the 1960s, Alfa Romeo cars have a particular "fault": second gear (manual) is very hard to enter, so it needs the driver to pass just for a fraction of second through the neutral gear (both in acceleration or in deceleration). This manoeuvre, called the "doppia" or "double Débraillée", distinguishes real drivers from "Sunday" ones.
See also: List of Italian companies