Roman law is the cradle of legal principles, which are embodied in the attainments of Roman legal jurisprudence as a most magnificent form of teleological jurisprudence in the history of law. Although legal principles have strongly contributed to the constitution of modern European legal systems, the proponents of theoretical jurisprudence generally consider that legal principles are not sources of law. Such an understanding is incompatible with the legal history and legal logic. Taking a mere glimpse into the legal history of the Roman-Germanic Slavonic legal family, one may conclude that quite a number of legal principles are unambiguously formulated in judicial practice (jurisprudence), even without relying on the explicit provisions envisaged in the applicable legal norms. Thus, judicial modeling of legal principles constituted the development of legal consciousness and conceptions that made the legal institutes comply with the 'spirit of time' and the 'nature of things'. Generally speaking, it can be said that legal principles express the objectives (teleology) of internal state law. Legal principles are teleological legal attitudes which bind together the existing legal norms and activities of legal entities, in line with the latitude and effects they have in the existing legal order. The legal principles are rooted in the causa of law-making sources, legal acts, legal relations and legal forms, which means that legal principles are the cornerstone and the ultimate objective of legal regulation as a whole. In addition, legal principles express 'a view upon the world' on different legal areas and on the state order as a whole. Consequently, legal principles serve as groundwork for defining the theory of state and law to such heights that further provide for observing the difference between legal orders, prominent legal systems and legal cultures. In this paper, the author examines the nature of the correlation between the principle of legal order and the principle of substantive internal law of the state. The most significant finding is that legal principles are deeply rooted in the institutional order of the territory-specific community, which is particularly reflected in the distinction between the consti­tution in formal terms and the constitution in absolute terms. The article further explains the correlations between legal principles, legal standards and legal norms. In particular, the author focuses on the legal nature of legal principles in relation to legal norms and legal rules, primary and secondary legal norms, and (specific) legal situations as the most important legal category in the legal order of a legal state. In the author's opinion, the conceptual framework of legal principles is the starting point for identifying and establishing legal situations which are crucial for shaping legal systems in the legal order of a legal state.