On most days, Vincent Ely Bad Heart Bull Jr. sits quietly in his four-wheel walker in a San Leandro shopping center, greeting passersby with a soft nod and a story to share. Now 70, he has spent 44 of those years in prison. But behind his weathered face lies a lineage that shaped the cultural memory of the Oglala Sioux for more than a century. “This isn’t just about me,” Vincent Jr. said. “It’s about where I come from.” His ancestry traces directly to Amos Bad Heart Bull, the renowned Oglala Sioux artist and chronicler whose late-1800s ledger drawings captured...