Princess Marie Louise of Bulgaria (Bulgarian: Княгиня Мария Луиза Българска; born 13 January 1933, Sofia) is the daughter of Tsar Boris III and Tsaritsa Ioanna and the older sister of Simeon II of Bulgaria.[1] Her baptism in the Bulgarian Orthodox Church caused controversy at the time because her mother had promised to raise her children as Catholics.[2] After the change in house laws into absolute primogeniture by her brother Simeon of Bulgaria, Princess Marie Louise became the head of the house of House of Saxe-Coburg and Gotha-Koháry.[3]