Already in 1888, the Moravian archaeologist Karel Jaroslav Maška described the site of Mounds. He recorded the report of the superintendent František Kropáč about a large fortification with a distinct moat about 3.5 km east of Mikulčice and a slightly more easterly unforested place “where nothing grows”, surrounded by a moat, with findings of pottery shards decorated with waves. The year 1954 was a milestone for the start of the fieldwork. The systematic excavations, which lasted continuously for 38 seasons, provided, thanks to their relative intactness, the most accessible material for the search for the history of Great Moravia to date and are associated with the names of academics Josef Poulik and Zdeněk Klanica.

The agglomeration lies in the Morava River floodplain in a landscape of floodplain forests. Its core consists of the main castle with two large adjacent outposts, one of which has the distinct character of a permanent military camp and the other appears more like a walled settlement. The somewhat elevated acropolis of the Great Moravian castle and the military outpost were protected by an almost identical wall of shell construction with a frontal stone rampart and moats formed by a set of arms of the Morava River.

On the highest point of the acropolis were two buildings representing the princely environment – the princely palace with a cast mortar floor and a stone fireplace and the basilica. Both buildings formed a separate precinct on the area of the so-called castle. A moat fortification was found around the palace and the basilica and the cemetery were separated by a palisade fence. The extensive three-aisled basilica with an atrium and a nartex – a chancel is the largest excavated Great Moravian religious building to date. In the area of the basilica and in the surroundings several tombs belonging to important representatives of the ruling class of Great Moravia, probably also to some of the Mojmir family, have been uncovered. Around the church, a burial ground of approximately 550 graves was uncovered, the density and overlapping of which indicate a considerable intensity of burials and therefore a relatively high population density. The burial site is distinguished by the abundance of rich graves with swords, gold and silver jewellery and lavish sets of belt fittings and silver and cast bronze terminals and gold buttons. These and many other finds represent masterful works of local craftsmanship. The arms have become a kind of unofficial symbol of the Mounds near Mikulčice, but the most valuable finds include a silver hanging cross with the figure of Christ and a gold solidus of the Byzantine emperor Michael III. A certain proof of education are also the findings of iron pens – styli.
The traces of metalworking and jewellery workshops in the castle are dated to the period before the middle of the 9th century.

The agglomeration also includes numerous hinterlands (settlement areas with burial mounds):

Northern and north-western substructure of Stepnice I (a proprietary church with unusual external aisles with 6 graves around, a church with a rectangular presbytery and 26 graves, southern sub-castle of Kostelisko (rotunda with 4 conchos and a cast mortar floor and simplified ancient mosaic with fragments of Roman bricks), eastern sub-castle, Těšický les – Klášterisko (two-apse rotunda, 200 graves, bronze gilded plaque, razor), Štěpnice II closer to Trapíkov (simple wooden rotunda on stone base, fragment of smoothed porphyritic slab, 16 graves, silver buttons, iron spurs), Frog (44 graves, glass beads, knives, pottery), 9th to 11th century Panské burial site, 9th century Trapíkov settlement,Kopčany with the preserved church of St. Margaret of Antioch, which has been preserved almost entirely in its original mass. The dating of the previously escaped church was made possible by the discovery of three Great Moravian graves with gilded buttons and silver drum earrings.
Other interesting finds from the agglomeration include the remains of a bridge, paved boats – monoxyles, fish catching pots, a spear, iron fish hooks, a wooden bucket, a bucket with decorative fittings, iron buckets inlaid with wood, three different types of war axes, wooden spoons and ladles, rope, iron smokers, sheep shears, iron scythe, sickle, scythe, iron whetstone, iron daggers, lead dagger, arrowheads, iron keys and lock fittings, bone skates, awls, crosspieces, antler needles, burnt clay horsetail, bone whistle. A small silver gilded reliquary in the shape of a miniature service book attracted special attention. Interestingly, there are abundant traces of food consumption of all kinds, especially in the Štěpnice forecourt, fortified with a wall of the same quality as the castle, but with no traces of crafts and other creative work, i.e. more of a barracks character.

Graves often overlap, sometimes the foundations of buildings. The finds date mainly from the 7th to 12th centuries.

Also worthy of attention is the major reconstruction of an older stone wall without signs of mere routine maintenance or some sudden catastrophe (fire, conquest, etc.) at Mikulčice Vale sometime in the mid-9th century. The rebuilt wall had a face stone wall significantly less massive. It seems as if the political importance of the original fortress declined here and only after the new public order did the new power representatives take care of the restoration of the ruined one, but not in its original meaning and with the former power aspirations. Prof. Poulik’s reflection on the centrality of the state may well have been valid for the first half of the 9th century.

Josef Poulik at the time thought of the Mikulčice agglomeration as the headquarters of the entire Great Moravian Empire, arguing that it was the strongest fortification yet found on the Great Moravian fortifications. However, this was true only until the fortifications in the Uherské Hradiště site of Rybárny were explored.