There are several Isaak Welch listed online. Please consider resubmitting your question to us again with more information so we can better assist you.
Isaak and I
Isaak IX would be Isaak the 9th.
Isaak Magiton's birth name is Magiton, Isaak Semyonovich.
Isaak Makhlis's birth name is Makhlis, Isaak Petrovich.
Isaak Shvarts's birth name is Shvarts, Isaak Iosifovich.
Chris Isaak's birth name is Christopher Joseph Isaak.
Isaak Babel's birth name is Isaak Emmanuilovich Babel.
Isaak Shmaruk's birth name is Shmaruk, Isaak Petrovich.
Isaak Mazel was born in 1911.
Isaak Mazel died in 1943.
Isaak Bacharach died in 1942.
Isaak Bacharach was born in 1854.