One major difference between Old Frisian and modern Frisian is that in the Old Frisian period ( – ) grammatical cases still occurred. Some of the texts that are preserved from this period are from the 12th or 13th, but most are from the 14th and 15th centuries. Generally, these texts are restricted to legal documents. Although the earliest definite written examples of Frisian are from approximately the 9th century, there are a few runic inscriptions from the region which are probably older and possibly in the Frisian language. These runic writings, however, usually do not amount to more than single- or few-word inscriptions, and cannot be said to constitute literature as such. The Middle Frisian language period ( – ) is rooted in geopolitics and the consequent fairly abrupt halt in the use of Frisian as a written language.