A new Chamber of Deputies is installed by the Mesa de Decanos, the Table of Deans. Under Article 15 of the Organic Law of the Congress, its members are the deputies-elect “que hayan desempeñado con mayor antigüedad la responsabilidad de legislador federal” (who have served longest as federal legislators).
If two have equal seniority, the one who has belonged to more legislatures comes first. If they are still tied, the older one does. The Table swears in the new legislators and presides over the session that elects the chamber’s first leadership.