Possessions

It was a dangerous trade for the “sandalwooders,” who often knew nothing of the people they encountered, with disastrous results. There were massacres of natives and massacres of sailors on the trading vessels. The Europeans could not appreciate a gift basket of human flesh; the “savages” resented brutal reprisals when they helped themselves to the possessions of these strange white men.

In the above sentence I don't quite understand when they helped themselves to the possessions of white men.

Does this mean the savages stole white men's belongings?

Thanks in advance!!