The present study investigated children's understanding that an object's history may increase its significance, an appreciation that underpins the concept of historical authenticity (i.e., the idea that an item's history determines its true identity, beyond its functional or material qualities, leading people to value real items over copies or fakes). We examined the development of historical significance through the lens of parent-child conversations, and children's performance on an authenticity assessment. The final sample was American, 79.2% monoracial White, and mid-high socio-economic status (SES) and included 48 parent-child pairs: 24 with younger children (R=3.5 to 4.5 years) and 24 with older children (R=5.5 to 6.5 years). Parent-child pairs discussed three books we created, with three storylines: a museum (culturally authentic) storyline, a clean-up (personally authentic) storyline, and a control storyline. Across measures, conversations suggested that authenticity may begin as a "placeholder concept" that is initially rooted in a broad appreciation for the significance of old objects and only later filled in with specifics. This placeholder initially directs children's learning about authenticity by linking, in an unspecified way, the value and significance of objects to their past. For example, we found that young children appropriately appealed to history (vs. perceptual or functional features of objects) in contexts regarding authentic objects but struggled in determining which objects were more significant on the post-test assessment, suggesting that they attend to object history but are not yet sure how histories matter for making authenticity judgments. We also found some evidence that directing children's attention toward conceptual information related to object history may in turn direct them away from material or perceptual considerations, as seen in trade-offs in parents' and children's conversations. Together, this exploratory report offers many new avenues for work on the development of authenticity concepts in childhood.