Complex sentence: His date of birth is unknown, as it took place at a time when there was no birth registration.His biographer, Philip Short, gives February 1898 as the most likely date.
Split into simpler sentences: His date of birth is unknown, and as it took place at a time when there was no birth registration. While it is impossible to state a precise year, his biographer, Philip Short, gives February 1898 as the most likely date.