Past Participle
The past participle in Middle High German is formed by prefixing "ge-" to the verb stem, in addition to a dental suffix ("-d-" or "-(e)t-") for weak verbs, or by prefixing "ge-" to the infinitive of a strong verb, with a possible vowel change in the stem. The past participle of "sëhen" is "gesëhen"; the past participle of "dienen" is "gedienet". These are general rules with many exceptions. As in English, the past participle can be used as part of a verbal phrase to form tenses (e.g., perfect, pluperfect), and as an adjective.
Read more about this topic: Middle High German Verbs, Verb Forms