The thesis of this work relates to the heraldic and diplomatic analysis of 16 grants of arms of Croatian and Slavonian nobility issued by Croatian-Hungarian kings Rudolph II, Ferdinand II and Ferdinand III . It is a question of yet unpublished material which is being conserved in the Croatian State Archive, in the holding Armales under the call number HR-HDA 885. Chronologically, these grants of arms are set in the period of 16th and 17th century, written in humanistics, in Latin language, whereas the material on which they were created is the parchment paper. In the framework of heraldic analysis the basics that were carried out were: descriptions of shields of the coats of arms and figures on them, discriptions of helmets above them, crowns and figures above shields. All of the coats of arms were afterwards mutually compared one to another on the basis of particularities which were encountered during the heraldic analysis. In the framework of diplomatic analysis, the grants of arms were divided into joints on the basics of their external (handwriting material, the color of the ink, the seal…) and internal (invocation, intitulation, arenga…) features and all of the grants of arms were, as carried out in the heraldic analysis, mutually compared one to another on the basics of these features. During the research, it has been noticed that several of these grants of arms deviated from common heraldic and diplomatic standards and several of them were considerably damaged due to the poor conservation, which presented significant difficulties in further analysis. Except the grants of arms, no further information on historical background of these families has been found, apart from the holding Maps of nobility (call number HR-HDA 884), which also has not been much of the help. However, in spite of all of the mentioned drawbacks and exceptions, it can be clearly stated that most of the grants of arms abide by all heraldic and diplomatic rules.