A regent, from the Latin regens ("one who reigns"), is a person selected to act as head of state (ruling or not) because the ruler is a minor, not present, or debilitated.
On behalf of the infant king Кoloman I Asen (1241–1246), the country was ruled by a regency.
When he died, a regency council led by Irina Komnina ruled on behalf of King Michael II Asen from 1246–1253.
A regency council on behalf of Ivan IV Smilets headed by his mother Smiltsena and despot Eltimir ruled from 1298–1299.
Stefan Stambolov, Sava Mutkurov and Petko Karavelov (replaced by Georgi Zhivkov) were regents after the abdication of Prince Alexander Battenberg in August 1886 until the election and inauguration of the new Prince Ferdinand I Saxe-Coburg-Gotha in August 1887.