Siculeni or Madéfalva (Siculeni, Madéfalva) is a commune in Harghita County, Romania.
The Massacre at Madéfalva of January 7th 1764 took place here. 200 Székely were executed by Maria Theresa of Austria's Habsburg army as the local Székely Hungarians refused to join the Austrian armed forces. Following this the Székely people began to flee the region crossing the Carpathian Mountains into Bukovina and Moldova to the east. The massacre's Latin name is Siculicidium (SICVLICIDIVM), which interestingly enough spells out the year 1764 in Roman Numerals if one removes the S at the beginning. A monument to the massacre was erected on October 8th 1905.