Quia propter

Quia propter was a document issued by the Fourth [Lateran Council] in 1215 on the subject of papal elections. It recognized three processes for unanimous agreement: "acclamation", "scrutiny", and "compromissum".
Acclamation was rare, and often driven more by crowd dynamics than discussion among the electors. Compromise committees were also rare, as they required unanimous agreement to be initiated. The requisite majority by balloting was considered a process for determining divine unanimity, that is, sanior et maior pars. The requirement of a two-thirds supermajority had been in place since the Third Lateran Council, which followed the disputed election of Pope [Alexander III].