diff --git a/README.md b/README.md
index 7b070ad..2b4f388 100644
--- a/README.md
+++ b/README.md
@@ -42,6 +42,21 @@ or add the following to your `project.clj` ([Leiningen](https://leiningen.org/))
 (h/render [:html [:body ...]])
 ```
 
+## Differences between Lambda Island Hiccup and other implementation.
+
+We try to minimize differences between Lambda Island Hiccup and Reagent, first
+and foremost. Whenver possible, we try to minimize differences between between Lambda Island Hiccup and the original Hiccup as well.
+
+There are no known semantic differences in the resulting HTML, but there are some minor differences if
+you are comparing the output character-for-character and one runtime
+difference:
+
+* When attributes are specified in both the tag name and a map, attributes may appear in a different order.
+* The CSS in `style` attributes has different whitespace.
+* Illegal tags throw `clojure.lang.ExceptionInfo`, instead of
+    `IllegalArgumentException`, as in Hiccup, or `AssertionError`, as in Reagent.
+
+
 <!-- opencollective -->
 ## Lambda Island Open Source
 
diff --git a/src/lambdaisland/hiccup.clj b/src/lambdaisland/hiccup.clj
index 007df5e..eda0bd5 100644
--- a/src/lambdaisland/hiccup.clj
+++ b/src/lambdaisland/hiccup.clj
@@ -89,7 +89,7 @@
         (= :<> tag)
         (enlive/flatmap #(nodify % opts) more)
 
-        (keyword? tag)
+        (or (keyword? tag) (symbol? tag) (string? tag))
         (let [[tag-name & segments] (.split (name tag) "(?=[#.])")
               id (some (fn [^String seg]
                          (when (= \# (.charAt seg 0)) (subs seg 1))) segments)
@@ -107,7 +107,8 @@
                                   (map (fn [[k v]]
                                          [(convert-attribute k) v]))
                                   (into {}))))
-              node (if id (assoc-in node [:attrs :id] id) node)
+             node (if (and id (not (contains? (:attrs node) :id))) 
+                     (assoc-in node [:attrs :id] id) node)
               node (if (seq classes)
                      (update-in node
                                 [:attrs "class"]
diff --git a/test/lambdaisland/hiccup_test.clj b/test/lambdaisland/hiccup_test.clj
index 2abbaf1..3e93b61 100644
--- a/test/lambdaisland/hiccup_test.clj
+++ b/test/lambdaisland/hiccup_test.clj
@@ -76,3 +76,95 @@
         (is (= (str "<div " expected "=\"baz\"></div>")
                (hiccup/render [:div {input "baz"}]
                               {:doctype? false})))))))
+;borrowed from Hiccup:
+
+(defmacro html [& body]
+  `(hiccup/render ~@body {:doctype? false}))
+
+(deftest tag-names
+  (testing "basic tags"
+    (is (= (str (html [:div])) "<div></div>"))
+    (is (= (str (html ["div"])) "<div></div>"))
+    (is (= (str (html ['div])) "<div></div>")))
+  (testing "tag syntax sugar"
+    (is (= (str (html [:div#foo])) "<div id=\"foo\"></div>"))
+    (is (= (str (html [:div.foo])) "<div class=\"foo\"></div>"))
+    (is (= (str (html [:div.foo (str "bar" "baz")]))
+           "<div class=\"foo\">barbaz</div>"))
+    (is (= (str (html [:div.a.b])) "<div class=\"a b\"></div>"))
+    (is (= (str (html [:div.a.b.c])) "<div class=\"a b c\"></div>"))
+    (is (= (str (html [:div#foo.bar.baz]))
+           "<div id=\"foo\" class=\"bar baz\"></div>"))))
+
+(deftest tag-contents
+  (testing "empty tags"
+    (is (= (str (html [:div])) "<div></div>"))
+    (is (= (str (html [:h1])) "<h1></h1>"))
+    (is (= (str (html [:script])) "<script></script>"))
+    (is (= (str (html [:text])) "<text></text>"))
+    (is (= (str (html [:a])) "<a></a>"))
+    (is (= (str (html [:iframe])) "<iframe></iframe>"))
+    (is (= (str (html [:title])) "<title></title>"))
+    (is (= (str (html [:section])) "<section></section>"))
+    (is (= (str (html [:select])) "<select></select>"))
+    (is (= (str (html [:object])) "<object></object>"))
+    (is (= (str (html [:video])) "<video></video>")))
+  (testing "void tags"
+    (is (= (str (html [:br])) "<br />"))
+    (is (= (str (html [:link])) "<link />"))
+    (is (= (str (html [:colgroup {:span 2}])) "<colgroup span=\"2\"></colgroup>"))
+    (is (= (str (html [:colgroup [:col]])) "<colgroup><col /></colgroup>")))
+  (testing "tags containing text"
+    (is (= (str (html [:text "Lorem Ipsum"])) "<text>Lorem Ipsum</text>")))
+  (testing "contents are concatenated"
+    (is (= (str (html [:body "foo" "bar"])) "<body>foobar</body>"))
+    (is (= (str (html [:body [:p] [:br]])) "<body><p></p><br /></body>")))
+  (testing "seqs are expanded"
+    (is (= (str (html [:body (list "foo" "bar")])) "<body>foobar</body>"))
+    (is (= (str (html (list [:p "a"] [:p "b"]))) "<p>a</p><p>b</p>")))
+  (testing "vecs don't expand - error if vec doesn't have tag name"
+    (is (thrown? clojure.lang.ExceptionInfo
+                 (html (vector [:p "a"] [:p "b"])))))
+  (testing "tags can contain tags"
+    (is (= (str (html [:div [:p]])) "<div><p></p></div>"))
+    (is (= (str (html [:div [:b]])) "<div><b></b></div>"))
+    (is (= (str (html [:p [:span [:a "foo"]]]))
+           "<p><span><a>foo</a></span></p>"))))
+
+(deftest tag-attributes
+  (testing "tag with blank attribute map"
+    (is (= (str (html [:xml {}])) "<xml></xml>")))
+  (testing "tag with populated attribute map"
+    (is (= (str (html [:xml {:a "1", :b "2"}])) "<xml a=\"1\" b=\"2\"></xml>"))
+    (is (= (str (html [:img {"id" "foo"}])) "<img id=\"foo\" />"))
+    (is (= (str (html [:img {'id "foo"}])) "<img id=\"foo\" />"))
+    (is (= (str (html [:xml {:a "1", 'b "2", "c" "3"}]))
+           "<xml a=\"1\" b=\"2\" c=\"3\"></xml>")))
+  (testing "attribute values are escaped"
+    (is (= (str (html [:div {:id "\""}])) "<div id=\"&quot;\"></div>")))
+  (testing "boolean attributes"
+    #_(is (= (str (html [:input {:type "checkbox" :checked true}]))
+           "<input type=\"checkbox\" checked=\"checked\" />"))
+    (is (= (str (html [:input {:type "checkbox" :checked false}]))
+           "<input type=\"checkbox\" />")))
+  (testing "nil attributes"
+    (is (= (str (html [:span {:class nil} "foo"]))
+           "<span>foo</span>")))
+  (testing "vector attributes"
+    (is (= (str (html [:span {:class ["bar" "baz"]} "foo"]))
+           "<span class=\"bar baz\">foo</span>"))
+    (is (= (str (html [:span {:class ["baz"]} "foo"]))
+           "<span class=\"baz\">foo</span>"))
+    (is (= (str (html [:span {:class "baz bar"} "foo"]))
+           "<span class=\"baz bar\">foo</span>")))
+  (testing "map attributes"
+    (is (= (str (html [:span {:style {:background-color :blue, :color "red",
+                                      :line-width 1.2, :opacity "100%"}} "foo"]))
+           "<span style=\"background-color: blue;\n  color: red;\n  line-width: 1.2;\n  opacity: 100%;\">foo</span>"))) ;format tweaked from original to match our format
+  (testing "resolving conflicts between attributes in the map and tag"
+    (is (= (str (html [:div.foo {:class "bar"} "baz"]))
+           "<div class=\"foo bar\">baz</div>"))
+    (is (= (str (html [:div.foo {:class ["bar"]} "baz"]))
+           "<div class=\"foo bar\">baz</div>"))
+    (is (= (str (html [:div#bar.foo {:id "baq"} "baz"]))
+           "<div id=\"baq\" class=\"foo\">baz</div>")))) ;swapped order from original test