The development of Copper Age tumulus in the territory of Montenegro went through several stages.
The initial phase is represented by the central pit grave within the ﬁrst mound of the Gruda Boljevića tumulus. This initial burial was dated to the beginning of the third millennium BC. Culturally it belongs to the southwestern branch of the Yamnaya culture, characterized by pit grave burials.
The next phase in the Copper Age tumulus development are represented by Velika Gruda and Mala Gruda tumuluses, which was dated to the period between the 3000 and 2800 BC. Mala and Velika Gruda tumuluses also have central pit burial. But this time the body was not placed directly into the pit. First a shallow grave pit was dug into the earth to the depth of half a meter. Then a stone cist was built inside the pit. First the bottom of the grave pit was covered with a stone plate and then the vertical stone plates were placed on top of it to form the dolmen cist. The body was placed inside the stone cist and then the cover stone plate was placed on top of it. The stone dolmen cist which was sticking out of the pit was then covered with a tumulus pile.
The final phase in the Copper Age tumulus development is represented by the Mogila na Rake and Bjelopavlići tumuluses. These two tumuluses were dated to the period between 2700 and 2400 BC. These two tumuluses also have a central burial withing a stone cist. But this time this stone cist is free standing on the surface of the earth. There is no trace of a burial pit any more. I don’t have detailed description of the Bjelopavlići tumulus but I do for the Mogila na Rake tumulus. The stone cist was built on a base which was round in shape, and made of medium and small pieces of limestone (0.5 to 0.20 m) mixed with red-brown earth. The cist was built on this layer using local stones. The sides were constructed from massive trapezoidal shape stone plates (1.40 × 1.00 m, about 20 cm thick), which were bonded with yellow waterproof clay. The body was placed inside the cist, and the cist was then covered with two massive rectangle shaped plates (1m x 1.20m and 1.80 × 1 m; 20 cm thick). After the cist was covered the dolmen cist was then covered with a tumulus pile.
The Late Copper age Montenegrian tumuluses have several common elements:
1. a central position of the burial within a large multi layered tumulus with stone curb
2. a cross in circle symbol inscribed either on a golden disc which topped the axe shaft hole or on ceramic vesel, which was interpreted as thurible and which was part of a special funerary ceramic set.
3. placing of food vessels inside the burial
These common elements show clear cultural continuity.
But at the same time the actual burial underwent a significant change:
1. a burial inside a pit with or without a cist dug into the ground
2. a burial inside a cist sticking out of a pit which was dug into the ground
3. a burial inside a free standing cist built on the surface of the ground.
This shows clear cultural development.
So by 2500 BC in Montenegro we find massive stone burial dolmen like cists which were placed on the surface of the ground and then covered by multi layered earth tumuluses with stone curbs.