Short answer. Usually one-third, not one-half. Article 900 cuts the sole surviving spouse's legitime to one-third where the marriage was solemnised in articulo mortis and the testator died within three months of it — unless the couple had already lived as husband and wife for more than five years.
What the law says
If the only survivor is the widow or widower, she or he shall be entitled to one-half of the hereditary estate of the deceased spouse, and the testator may freely dispose of the other half.
Civil Code, Article 900 — Legitime Of Sole Surviving Spouse. Read the full provision →
What the law says
If the marriage between the surviving spouse and the testator was solemnized in articulo mortis, and the testator died within three months from the time of the marriage, the legitime of the surviving spouse as the sole heir shall be one-third of the hereditary estate, except when they have been living as husband and wife for more than five years.
Civil Code, Article 900 — Legitime Of Sole Surviving Spouse. Read the full provision →
Two different fractions for the same widow
Article 900 sets two figures for one person and the facts decide which applies. The default sits in the first sentence: if the only survivor is the widow or widower, she or he shall be entitled to one-half of the hereditary estate of the deceased spouse, and the testator may freely dispose of the other half. The second paragraph then carves out the deathbed marriage. Where the wedding was solemnised in articulo mortis and the spouse died soon after, the legitime of the surviving spouse as sole heir falls to one-third, which leaves two-thirds disposable by will instead of one-half.
Both conditions have to line up
The reduction bites only if two facts are established, and each is a matter of proof rather than of anybody's intention. The marriage must have been solemnised in articulo mortis — at the point of death — which is why the solemnising officer's affidavit and the clinical record of the days around the ceremony carry so much weight. And the testator must have died within three months from the time of the marriage. A spouse who married from a hospital bed but survived four months leaves the ordinary one-half legitime untouched. The calendar does the work here, not the diagnosis.
The five-year clause families overlook
The exception at the end of the paragraph often settles the whole dispute. The one-third rule applies except when they have been living as husband and wife for more than five years, and where that is shown, the legitime of the surviving spouse shall be that specified in the preceding paragraph — one-half again. The provision is aimed at the marriage contracted at the very end to redirect an estate, not at a long partnership formalised late. A couple who lived together openly for a decade and married in the final week fall outside it, so proving those years usually matters more than arguing about the ceremony.
What the one-third is taken from
Two boundaries are worth keeping straight before anyone starts dividing. This article governs the widow or widower as sole heir; if children or parents also survive, other provisions fix the shares and the one-third figure has no application at all. And a legitime is not the same thing as the survivor's share on liquidation of the marriage's property regime — what she takes as her half of the community or conjugal assets belongs to her in her own right and never enters the hereditary estate the fraction is measured against. Establish what the estate actually consists of first.