shortened: "oe" to "e", and "ae" to "e". Thus, "oecumenicus" becomes the more familiar "ecumenicus" (more familiar in this later form because religious terms such as "ecumenical" were more common in medieval Latin). The "oe" diphthong is not particularly frequent in Latin, but the shift from "ae" to "e" affects many common words, such as "caelum" (heaven) being shortened to "celum"; even "puellae" (girls) was shortened to "puelle". Often, a town would lose its name to that of the tribe which was either accusative or ablative plural; two forms that were then used for all cases, or in other words, considered "indeclinable". Orthography Many striking differences between classical and medieval Latin are found in orthography. Perhaps the most striking difference is that medieval manuscripts used a wide range of abbreviations by means of superscripts, special characters etc.: for instance the letters "n" and "s" were often omitted and replaced by a diacritical mark above the preceding or following letter. Apart from this, some of the most frequently occurring differences are as follows. Clearly many of these would have been influenced by the spelling, and indeed pronunciation, of the vernacular language, and thus varied between different European countries. Following the Carolingian reforms of the 9th century, Carolingian minuscule was widely adopted, leading to a clear differentiation between capital and lowercase letters. A partial or full differentiation between v and u, and between j and i. The diphthong ae is usually collapsed and simply written as e (or e caudata, ę); for example, puellae might be written puelle (or puellę). The same happens with the diphthong oe, for example in pena, Edipus, from poena, Oedipus. This feature is already found on coin inscriptions of the 4th century (e.g. for reipublicae). Conversely, an original e in Classical Latin was often represented by ae or oe (e.g. aecclesia and coena), also reflected in English spellings such as foetus. Because of a severe decline in the knowledge of Greek, in loanwords and foreign names from or transmitted through Greek, y and i might be used more or less interchangeably: Ysidorus, Egiptus, from Isidorus, Aegyptus. This is also found in pure Latin words: ocius ("more swiftly") appears as and silva as sylva, this last being a form which survived into the 18th century and so became embedded in modern botanical Latin (also cf. Pennsylvania). h might be lost, so that habere becomes abere, or mihi becomes