John Wycliffe (1380s), used the spelling
Ihesus, and also used
Ihesu ('J' was then a swash glyph variant of 'I', not considered to be a separate letter until much later) in
oblique cases, and also in the accusative, and sometimes, apparently without motivation, even for the nominative.
Tyndale in the 16th century has the occasional
Iesu in oblique cases and in the vocative; The 1611
King James Version uses
Iesus throughout, regardless of syntax.
Jesu came to be used in English, especially in
hymns.
https://en.wikipedia.org/wiki/Jesus_(name)