POSTGRESQL'S ancestor was Ingres, developed at the University of California at Berkeley (1977-1985). The Ingres code was later enhanced by Relational Technologies/Ingres Corporation,6.1 which produced one of the first commercially successful relational database servers. Also at Berkeley, Michael Stonebraker led a team to develop an object-relational database server called Postgres (1986-1994). Illustra 6.2 took the Postgres code and developed it into a commercial product. Two Berkeley graduate students, Jolly Chen and Andrew Yu , subsequently added SQL capabilities to Postgres. The resulting project was called Postgres95 (1994-1995). The two later left Berkeley, but Chen continued maintaining Postgres95, which had an active mailing list.