Early societies often sought the truth through cruel and brutal physical ordeals on the belief that God would protect the innocent and punish the guilty. Methods included ordeals by combat, fire and water, and trial by compurgation. These primitive methods did not involve any element of persuasion or concern with the reliability of the tests involved or with witness credibility. The development of the jury system in the common law introduced the element of persuasion through the presentation of evidence to substantiate claims and allegations. Legal jurisprudence and judicial decisions established rules regarding the presentation of evidence for the determination of guilt or innocence. Evidence includes direct evidence, circumstantial evidence, and real evidence. Crucial issues include admissibility and relevancy. Spontaneous declarations preceding, accompanying, or immediately following a criminal act are admitted in evidence as an exception to the rule against hearsay evidence. The courts are always in a state of flux regarding evidence; United States Supreme Court decisions frequently redefine the admissibility of evidence.