The Lambergs held one of the most extensive estates not only in Carniola but also in other Habsburg provinces. In fact, so extensive was their estate in the seventeenth century that the polymath Johann Weikhard von Valvasor dedicated a special topography to it and published it in an independent booklet at Bogenšperk in 1670. A multitude of family members subsequently led to the creation of many lines and branches named after the most important seigniories—that is, the Črnelo (Rottenbichell) line, Gutenberg-Kamen, and Ortenegg-Ottenstein, as well as Snežnik, Poppendorf, and Boštanj.
One of the Lamberg estates was Brdo pri Lukovici. Where now its ruins lie, a manor stood in the fifteenth century that Johann von Lamberg from Črnelo had converted in the mid-sixteenth century into a fortified Renaissance mansion. The restoration was completed by his son Andreas from Črnelo and Jablje (Habach). The year 1552, carved in the memorial heraldic plaque above the castle entrance, may be taken as an indicative year in which construction work was completed. The inscription states in its entirety as follows: DAS·GEBAY·HAT·DER·EDL· / VND·GESTRENG·HER= / R·HANS·VON·LAMBER= / G·ZVM·ROTENPVH= / EL·VND·MÄNSPERG· / ZV·ERBAVEN·ONGEF= / ONGEN·NOHMOLS·D= / VRH·SEINEM·SVN· / ANDREN·VON·LOM= / BERG·ZVM·ROTENP= / VHEL·VND·HOBOCH· / MIT·GOTES·HILF· / VOLLENDT·BORDEN. This plaque has been surprisingly well preserved, given that the castle was burned down during the Second World War and left to systematic ruin after the war.
Except for Brdo Castle, Johann and Andreas von Lamberg left no visible traces. Johann was the oldest son of Sigismund II von Lamberg, the hunting master of the court and King Ferdinand’s educator. Apart from two sisters, he also had three brothers, of whom Andreas is believed to have been the founder of the early modern Jablje Castle (Habach) and Georg the founder of the early modern Zaprice Castle (Steinbüchel). Johann was married to his cousin Kirchfelda von Obratschan, with whom he fathered eight children. None of the five sons appear to have continued the family branch, even though at least two (Casper and Sigismund) were married. Because Andreas, the successor of his father Johann at Brdo, remained a bachelor, the castle was inherited by his close relatives until they first pledged it in 1622 and sold it a few years later. This sales transaction was characteristic for the Lambergs’ family policy from the seventeenth century onward, which slowly but consistently led the family away from Slovenian territory and to other Habsburg provinces. The ties between the Lambergs and the Slovenian provinces ultimately broke in 1810, after Johann Nepomuk Count von Lamberg from the main Gutenberg-Kamen line sold the merged seigniories in Begunje, Kamen, and Katzenstein, and moved to Kvasice Castle in Moravia.

Sources:
Jakič, Ivan: Vsi slovenski gradovi, Ljubljana: DZS, 1999, p. 67.
Kos, Dušan: Turnirska knjiga Gašperja Lambergerja. Ljubljana, 1997.
Potočnik, Mitja: Grad Brdo skozi stoletja. Novo Mesto, 2008.
Smole, Majda: Graščine na nekdanjem Kranjskem. Ljubljana, DZS, 1982.
Stopar, Ivan: Grajske stavbe v osrednji Sloveniji. I. Gorenjska. Območje Kamnika in Kamniške Bistrice (vol. 7). Ljubljana 1997, pp. 12–17.