diff --git a/webapp/src/edu/cornell/mannlib/vitro/webapp/edit/elements/DateTimeWithPrecision.java b/webapp/src/edu/cornell/mannlib/vitro/webapp/edit/elements/DateTimeWithPrecision.java
index c0fb0d179..2f4c4b7d4 100644
--- a/webapp/src/edu/cornell/mannlib/vitro/webapp/edit/elements/DateTimeWithPrecision.java
+++ b/webapp/src/edu/cornell/mannlib/vitro/webapp/edit/elements/DateTimeWithPrecision.java
@@ -133,7 +133,7 @@ public class DateTimeWithPrecision extends BaseEditElement {
             		"'" + precisionUri + "' but could not convert to Precision object");
         }
         
-        if( precisionUri == null || precisionUri.isEmpty()  ){
+        if( precisionUri == null || precisionUri.isEmpty() || existingPrec == null){
             map.put("existingPrecision", "");
             
             /* no precision so there should also be no datetime */
@@ -168,24 +168,35 @@ public class DateTimeWithPrecision extends BaseEditElement {
                         + " but the date time is " + value);                        
             
             /* only put the values in the map for ones which are significant based on the precision */
-            if( existingPrec.ordinal() >= VitroVocabulary.Precision.SECOND.ordinal() ){
+            if( existingPrec.ordinal() >= VitroVocabulary.Precision.SECOND.ordinal() )
                 map.put("second", Integer.toString(value.getSecondOfMinute() )) ;
-            }
-            if( existingPrec.ordinal() >= VitroVocabulary.Precision.MINUTE.ordinal()  ){
+            else
+                map.put("second", "");
+            
+            if( existingPrec.ordinal() >= VitroVocabulary.Precision.MINUTE.ordinal()  )
                 map.put("minute", Integer.toString(value.getMinuteOfHour()) );    
-            }
-            if( existingPrec.ordinal() >= VitroVocabulary.Precision.HOUR.ordinal() ){
-                map.put("hour", Integer.toString(value.getHourOfDay()) );            
-            }
-            if( existingPrec.ordinal() >= VitroVocabulary.Precision.DAY.ordinal()  ){
+            else
+                map.put("minute", "");
+            
+            if( existingPrec.ordinal() >= VitroVocabulary.Precision.HOUR.ordinal() )
+                map.put("hour", Integer.toString(value.getHourOfDay()) );
+            else
+                map.put("hour", "");
+            
+            if( existingPrec.ordinal() >= VitroVocabulary.Precision.DAY.ordinal()  )
                 map.put("day", Integer.toString(value.getDayOfMonth()) );                    
-            }
-            if( existingPrec.ordinal() >= VitroVocabulary.Precision.MONTH.ordinal() ){
+            else
+                map.put("day", "");
+            
+            if( existingPrec.ordinal() >= VitroVocabulary.Precision.MONTH.ordinal() )
                 map.put("month", Integer.toString(value.getMonthOfYear()));                            
-            }
-            if( existingPrec.ordinal() >= VitroVocabulary.Precision.YEAR.ordinal() ){
+            else
+                map.put("month", "");
+            
+            if( existingPrec.ordinal() >= VitroVocabulary.Precision.YEAR.ordinal() )
                 map.put("year", Integer.toString(value.getYear()));                  
-            }
+            else
+                map.put("year", "");
         }               
         
         return map;
diff --git a/webapp/src/edu/cornell/mannlib/vitro/webapp/edit/n3editing/DateTimeIntervalValidation.java b/webapp/src/edu/cornell/mannlib/vitro/webapp/edit/n3editing/DateTimeIntervalValidation.java
new file mode 100644
index 000000000..38f6456e4
--- /dev/null
+++ b/webapp/src/edu/cornell/mannlib/vitro/webapp/edit/n3editing/DateTimeIntervalValidation.java
@@ -0,0 +1,82 @@
+/* $This file is distributed under the terms of the license in /doc/license.txt$ */
+
+package edu.cornell.mannlib.vitro.webapp.edit.n3editing;
+
+import java.util.Calendar;
+import java.util.HashMap;
+import java.util.Map;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+
+import com.hp.hpl.jena.datatypes.xsd.XSDDateTime;
+import com.hp.hpl.jena.rdf.model.Literal;
+
+public class DateTimeIntervalValidation implements N3Validator {
+    private static Log log = LogFactory.getLog(DateTimeIntervalValidation.class);
+    
+    private String startFieldName;
+    private String endFieldName;
+
+    private String startValueName;
+    private String endValueName;
+    
+    public DateTimeIntervalValidation(String startFieldName, String endFieldName){
+        this.startFieldName = startFieldName;
+        this.endFieldName = endFieldName;
+        startValueName = startFieldName + ".value";
+        endValueName = endFieldName + ".value";
+    }
+    
+    public Map<String, String> validate(EditConfiguration editConfig,
+            EditSubmission editSub) {
+        Map<String, Literal> existingLiterals = editConfig.getLiteralsInScope();
+        Literal existingStartYear = existingLiterals.get(startValueName);
+        Literal existingEndYear = existingLiterals.get(endValueName);
+
+        Map<String, Literal> literalsFromForm = editSub.getLiteralsFromForm();
+        Literal formStartYear = literalsFromForm.get(startValueName);
+        Literal formEndYear = literalsFromForm.get(endValueName);
+
+        Map<String, String> errors = new HashMap<String, String>();
+
+        if (formStartYear != null && formEndYear != null) {
+            errors.putAll(checkDateLiterals(formStartYear, formEndYear));
+        } else if (formStartYear != null && existingEndYear != null) {
+            errors.putAll(checkDateLiterals(formStartYear, existingEndYear));
+        } else if (existingStartYear != null && formEndYear != null) {
+            errors.putAll(checkDateLiterals(existingStartYear, formEndYear));
+        } else if (existingStartYear != null && existingEndYear != null) {
+            errors.putAll(checkDateLiterals(existingStartYear, existingEndYear));
+        }
+
+        if (errors.size() != 0)
+            return errors;
+        else
+            return null;
+    }
+
+    private Map<String, String> checkDateLiterals(Literal startLit, Literal endLit) {
+        Map<String, String> errors = new HashMap<String, String>();        
+        try{
+             XSDDateTime startDate = (XSDDateTime)startLit.getValue();
+             XSDDateTime endDate = (XSDDateTime)endLit.getValue();
+             if( startDate != null && endDate!= null ){
+                 Calendar startCal = startDate.asCalendar();
+                 Calendar endCal = endDate.asCalendar();
+                                  
+                 if( endCal != null && ! endCal.after( startCal ) ){
+                     errors.put(startFieldName, "Start year must be before end year");
+                     errors.put(endFieldName, "End year must be after start year");
+                 }
+             }
+        }catch(ClassCastException cce){
+            errors.put(startFieldName, "could not format star or end date");
+            errors.put(endFieldName, "could not format star or end date");
+            log.debug("could not format dates " + cce);
+        }
+            
+        return errors;
+    }
+
+}