Muniment of title, at least in Texas, is a FORM of probate. What I call "regular probate," meaning with a will and with administration, has to be filed within four years of decedent's death. Probate as a muniment of title does NOT have the four-year requirement, theoretically it could be filed at any time as long as a "regular probate" case has not been initiated, and does NOT include administration of the Estate, just decides who gains title to the property.