JURISDICTION: ACTIONS WHICH ARE INCAPABLE OF PECUNIARY ESTIMATION FALL WITHIN THE JURISDICTION OF THE REGIONAL TRIAL COURTS

It is well-settled that jurisdiction over the subject matter is conferred by law.

Relative thereto, the statutory law vests on Regional Trial Courts exclusive original jurisdiction over civil actions incapable of pecuniary estimation.  

An action for specific performance, such as a suit to enforce the Agreement on Joint Child Custody, belongs to this species of actions.  Thus, jurisdiction-wise, it belongs to the RTC. (Dacasin vs. Dacasin, G.R. No. 168785, February 05, 2010, CARPIO, J.).