Short answer. The law in force when he died. Succession is fixed at the moment of death, so a grandfather who died before the present Civil Code took effect in 1950 has his estate governed by the old Civil Code of 1889, earlier statutes and the Rules of Court.
What the law says
before the effectivity of this Code, shall be governed by the Civil Code of 1889, by other previous laws, and by the Rules of Court
Civil Code, Article 2263 — Which Law Governs Succession. Read the full provision →
Death fixes the governing law
Article 2263 draws the line at the moment of death, not the date the estate is finally settled. Inheritance that opened before the effectivity of this Code, shall be governed by the Civil Code of 1889, by other previous laws, and by the Rules of Court. So it does not matter that the property is only being divided among the heirs now, decades later, or that everyone involved has lived their whole lives under the present Code. What the grandfather could dispose of, who his forced heirs were, and how large their shares had to be are read off the law in force on the day he died.
What the old law can change
The differences are not cosmetic. The Spanish Civil Code of 1889 used a different scheme of legitimes and of betterments, treated the surviving spouse and illegitimate children differently, and carried formalities for wills that the 1950 Code later altered. A disposition perfectly valid today might have been void then, and a share the present Code would give an heir might not have existed at all. This is why identifying the correct governing law is the first question, not a technicality: the whole computation of who gets what turns on it, and applying today's rules to a pre-1950 death produces a partition the law does not support.
Deaths after the Code took effect
The same article settles the mirror case. Where a person dies after the present Code began, the estate is adjudicated and distributed in accordance with this new body of laws, and any will is carried out so far as the Code permits. Even then the article protects vested expectations: legitimes, betterments, legacies and bequests shall be respected; however, their amount shall be reduced if in no other manner can every compulsory heir be given his full share according to this Code. So the reduction is the last resort, applied only when a forced heir would otherwise be shortchanged.
What settles it in your case
The one fact that decides everything is the exact date of death, so start with the death certificate or civil-registry record rather than family recollection of the year. Then establish whether he left a will, since a testate estate and an intestate one are computed differently under the old law just as under the new. With the date and the testate-or-intestate question answered, the applicable rules follow automatically, and a lawyer can tell you which version of the legitime and which formalities the estate must be measured against.
Cases citing this provision
These Supreme Court decisions cite the provision above. We list them so you can read them yourself; the summaries of what each decided are not ours to give.
- Elpidio Magno, et al. vs. Lorenzo Magno, et al, G.R. No. 206451, August 17, 2016 — read the decision on LawPhil →