This report summarizes the contextual background and processes of writing the 1987 Philippine Constitution, its contents and a preliminary mapping of its implementation, covering elections held under the Constitution, major laws enacted as mandated by the Constitution and critical judicial decisions of the Supreme Court interpreting provisions of the Constitution. The Chronology also covers impeachment cases under the Constitution, a timeline of the peace processes pursued from 1987–2018, and trend analysis of approval ratings of the officials and institutions created under the 1987 Constitution to measure citizens’ perceptions of the constitutional order. Research and writing of the Chronology was led by the research team at the University of the Philippines Center for Integrated Development Studies, under its project with International IDEA to complete a performance assessment of the 1987 Constitution. The Chronology is the first product of this collaboration and serves as the basis for the forthcoming performance assessment report.