Development of the banknote began in the Tang Dynasty during the 7th century, with local issues of paper currency, although true paper money did not appear until the 11th century, during the Song Dynasty.
A contract typically does not have to be notarized. A notary public (or simply notary) provides an acknowledgment that the signature appearing on the document is that of the person whose signature it purports to be. There is a requirement that some documents be notarized, such as a real property deed.
In acknowledging a person's signature, the notary is also attesting to the fact that the person signing appears to be mentally competent and does not appear to be signing under undue influence or coercion. Most individuals need to have their signature notarized on a document at some point in their life. It may be in connection with taking out a mortgage loan, signing a deed to convey real property, filing a mechanic's lien, executing a power of attorney, or signing estate planning documents.