diff --git a/.eleventy.js b/.eleventy.js
index 5597bec..1c19372 100644
--- a/.eleventy.js
+++ b/.eleventy.js
@@ -146,6 +146,16 @@ module.exports = function (eleventyConfig) {
     return encodeURIComponent(str);
   });
 
+  eleventyConfig.addFilter("toRomanNumerals", function (num) {
+    const vals = [1000,900,500,400,100,90,50,40,10,9,5,4,1];
+    const syms = ["M","CM","D","CD","C","XC","L","XL","X","IX","V","IV","I"];
+    let result = "";
+    for (let i = 0; i < vals.length; i++) {
+      while (num >= vals[i]) { result += syms[i]; num -= vals[i]; }
+    }
+    return result;
+  });
+
   eleventyConfig.addFilter("cssmin", function (code) {
     return new CleanCSS({}).minify(code).styles;
   });
diff --git a/_data/build.js b/_data/build.js
new file mode 100644
index 0000000..c0d5b49
--- /dev/null
+++ b/_data/build.js
@@ -0,0 +1,3 @@
+module.exports = {
+  year: new Date().getFullYear(),
+};
diff --git a/_includes/layouts/base.njk b/_includes/layouts/base.njk
index fb86a8a..5d999e3 100644
--- a/_includes/layouts/base.njk
+++ b/_includes/layouts/base.njk
@@ -111,7 +111,7 @@
     </main>
 
     <footer>
-      &copy; MCMLXXX
+      &copy; <abbr title="{{ build.year }}">{{ build.year | toRomanNumerals }}</abbr>
       <a href="/about/">{{ metadata.author.name }}</a>
       <a href="/site-index/">Index</a>
     </footer>