Complex sentence: Orphaned at an early age, he was raised by his mother's brother Fredrik Richter, a goldsmith, and was apprenticed to the painter David von Krafft in 1712.
Split into simpler sentences: Orphaned at an early age, he was raised by his uncle, Fredrik Richter, who was himself a goldsmith. Lundberg was later apprenticed to the painter David von Krafft in 1712.