Context: Spanish was nonetheless the only official language in Galicia for more than four centuries. Over the many centuries of Castilian domination, Galician faded from day-to-day use in urban areas. The period since the re-establishment of democracy in Spain—in particular since the Lei de Normalización Lingüística ("Law of Linguistic Normalization", Ley 3/1983, 15 June 1983)—represents the first time since the introduction of mass education that a generation has attended school in Galician (Spanish is also still taught in Galician schools).

Question: For how long was Spanish the official language of Galicia?
Answer: more than four centuries

Question: In modern times, from which year have children attended school in Galician?
Answer: 1983

Question: What was the name of the law that enacted this?
Answer: Lei de Normalización Lingüística ("Law of Linguistic Normalization"