This is the grave of Christo N. Brakalov, who financed the rebuilding effort of the monastery, to look as it does today.
http://www.pbase.com/image/43768098 The link would take you to Mr. Brakalov's house in the city of Kalofer.

Тук почива прахът на
Христо Н. Бракаловъ
докторъ на правото
роденъ въ г.КАЛОФЕРЪ 1856
починалъ въ г.ВИЕНА 1905