Complex sentence: The second vintage and the first that was produced at the estate and in commercial quantities was from 1973 and was entered into, and was rated the top red wine at the now historic Judgment of Paris in 1976, launching the winery into the international spotlight.
Split into simpler sentences: The second vintage--the first that was produced at the estate and in commercial quantities--was from 1973. This' 73 vintage was entered into and subsequently rated the top red wine at the now historic Judgment of Paris in 1976, launching the winery into the international spotlight.