Allies of Philippine President Ferdinand Marcos Jr looked set to win at least half of the available Senate seats in a midterm election on Monday, an unofficial tally showed, in a contest seen as a referendum on his leadership and a fierce proxy battle with his estranged vice president.

Here’s what to know about the crucial midterms and the rival dynasties at the heart of the Southeast Asian nation’s politics.

Philippine President Ferdinand Marcos Jr has been dealt an unexpected blow in the midterms, with his Senate candidates set to pick up fewer seats than expected, according to early results. The election was a showdown between Marcos and his Vice-President Sara Duterte, daughter of former president Rodrigo Duterte.