Research in cross-lingual modeling for historical and extremely low-resource languages is hindered by the absence of standardized evaluation benchmarks. To address this, we present ManCC—the first task-anchored benchmark for Manchu–Classical Chinese translation. ManCC consists of a high-quality parallel corpus of 16,627 sentence pairs, derived from the Qing-dynasty historical text Manwen Laodang-Taizong, and a reproducible evaluation protocol that combines automatic metrics (BLEU and chrF) with a three-dimensional human assessment (fidelity, fluency, linguistic normativity). Through systematic evaluation across three model families (non-pretrained, multilingual pretrained, and large language models), we find that linguistic differences significantly influence performance, broader language coverage in multilingual pretraining facilitates low-resource transfer, and automatic metrics often fail to capture essential errors in historical translation—underscoring the necessity of human evaluation. ManCC not only provides foundational resources for Manchu–Classical Chinese translation but also establishes a diagnosable, reproducible platform for cross-lingual modeling of historical low-resource languages.