diff --git a/quartz/plugins/transformers/frontmatter.ts b/quartz/plugins/transformers/frontmatter.ts
index 41c1b1375..eae359e1e 100644
--- a/quartz/plugins/transformers/frontmatter.ts
+++ b/quartz/plugins/transformers/frontmatter.ts
@@ -5,7 +5,6 @@ import yaml from "js-yaml"
 import toml from "toml"
 import { slugTag } from "../../util/path"
 import { QuartzPluginData } from "../vfile"
-import chalk from "chalk"
 
 export interface Options {
   delims: string | string[]
@@ -17,23 +16,6 @@ const defaultOptions: Options = {
   language: "yaml",
 }
 
-function coerceDate(fp: string, d: unknown): Date | undefined {
-  if (d === undefined || d === null) return undefined
-  const dt = new Date(d as string | number)
-  const invalidDate = isNaN(dt.getTime()) || dt.getTime() === 0
-  if (invalidDate) {
-    console.log(
-      chalk.yellow(
-        `\nWarning: found invalid date "${d}" in \`${fp}\`. Supported formats: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Date#date_time_string_format`,
-      ),
-    )
-
-    return undefined
-  }
-
-  return dt
-}
-
 function coalesceAliases(data: { [key: string]: any }, aliases: string[]) {
   for (const alias of aliases) {
     if (data[alias] !== undefined && data[alias] !== null) return data[alias]
@@ -66,7 +48,6 @@ export const FrontMatter: QuartzTransformerPlugin<Partial<Options> | undefined>
         [remarkFrontmatter, ["yaml", "toml"]],
         () => {
           return (_, file) => {
-            const fp = file.data.filePath!
             const { data } = matter(Buffer.from(file.value), {
               ...opts,
               engines: {
@@ -88,16 +69,6 @@ export const FrontMatter: QuartzTransformerPlugin<Partial<Options> | undefined>
             if (aliases) data.aliases = aliases
             const cssclasses = coerceToArray(coalesceAliases(data, ["cssclasses", "cssclass"]))
             if (cssclasses) data.cssclasses = cssclasses
-            const created = coerceDate(fp, coalesceAliases(data, ["created", "date"]))
-
-            if (created) data.created = created
-            const modified = coerceDate(
-              fp,
-              coalesceAliases(data, ["modified", "lastmod", "updated", "last-modified"]),
-            )
-            if (modified) data.modified = modified
-            const published = coerceDate(fp, coalesceAliases(data, ["published", "publishDate"]))
-            if (published) data.published = published
 
             // fill in frontmatter
             file.data.frontmatter = data as QuartzPluginData["frontmatter"]
@@ -120,9 +91,6 @@ declare module "vfile" {
         draft: boolean
         enableToc: string
         cssclasses: string[]
-        created: Date
-        modified: Date
-        published: Date
       }>
   }
 }
diff --git a/quartz/plugins/transformers/lastmod.ts b/quartz/plugins/transformers/lastmod.ts
index 193664d65..31c8c2084 100644
--- a/quartz/plugins/transformers/lastmod.ts
+++ b/quartz/plugins/transformers/lastmod.ts
@@ -12,6 +12,21 @@ const defaultOptions: Options = {
   priority: ["frontmatter", "git", "filesystem"],
 }
 
+function coerceDate(fp: string, d: any): Date {
+  const dt = new Date(d)
+  const invalidDate = isNaN(dt.getTime()) || dt.getTime() === 0
+  if (invalidDate && d !== undefined) {
+    console.log(
+      chalk.yellow(
+        `\nWarning: found invalid date "${d}" in \`${fp}\`. Supported formats: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Date#date_time_string_format`,
+      ),
+    )
+  }
+
+  return invalidDate ? new Date() : dt
+}
+
+type MaybeDate = undefined | string | number
 export const CreatedModifiedDate: QuartzTransformerPlugin<Partial<Options> | undefined> = (
   userOpts,
 ) => {
@@ -23,21 +38,23 @@ export const CreatedModifiedDate: QuartzTransformerPlugin<Partial<Options> | und
         () => {
           let repo: Repository | undefined = undefined
           return async (_tree, file) => {
-            let created: Date | undefined = undefined
-            let modified: Date | undefined = undefined
-            let published: Date | undefined = undefined
+            let created: MaybeDate = undefined
+            let modified: MaybeDate = undefined
+            let published: MaybeDate = undefined
 
             const fp = file.data.filePath!
             const fullFp = path.posix.join(file.cwd, fp)
             for (const source of opts.priority) {
               if (source === "filesystem") {
                 const st = await fs.promises.stat(fullFp)
-                created ||= new Date(st.birthtimeMs)
-                modified ||= new Date(st.mtimeMs)
+                created ||= st.birthtimeMs
+                modified ||= st.mtimeMs
               } else if (source === "frontmatter" && file.data.frontmatter) {
-                created ||= file.data.frontmatter.created
-                modified ||= file.data.frontmatter.modified
-                published ||= file.data.frontmatter.published
+                created ||= file.data.frontmatter.date as MaybeDate
+                modified ||= file.data.frontmatter.lastmod as MaybeDate
+                modified ||= file.data.frontmatter.updated as MaybeDate
+                modified ||= file.data.frontmatter["last-modified"] as MaybeDate
+                published ||= file.data.frontmatter.publishDate as MaybeDate
               } else if (source === "git") {
                 if (!repo) {
                   // Get a reference to the main git repo.
@@ -47,9 +64,7 @@ export const CreatedModifiedDate: QuartzTransformerPlugin<Partial<Options> | und
                 }
 
                 try {
-                  modified ||= new Date(
-                    await repo.getFileLatestModifiedDateAsync(file.data.filePath!),
-                  )
+                  modified ||= await repo.getFileLatestModifiedDateAsync(file.data.filePath!)
                 } catch {
                   console.log(
                     chalk.yellow(
@@ -61,13 +76,10 @@ export const CreatedModifiedDate: QuartzTransformerPlugin<Partial<Options> | und
               }
             }
 
-            created ||= new Date()
-            modified ||= new Date()
-            published ||= new Date()
             file.data.dates = {
-              created,
-              modified,
-              published,
+              created: coerceDate(fp, created),
+              modified: coerceDate(fp, modified),
+              published: coerceDate(fp, published),
             }
           }
         },