diff --git a/data/xml/meta.xml b/data/xml/meta.xml
index abaa01b..29887e1 100644
--- a/data/xml/meta.xml
+++ b/data/xml/meta.xml
@@ -2296,7 +2296,7 @@
 
 		<letterDesc letter="152">
 			<sent>
-				<date when="1776-04-01">Dessau, 4. April 1776</date>
+				<date when="1776-04-04">Dessau, 4. April 1776</date>
 				<location ref="25" />
 				<person ref="34" />
 			</sent>
@@ -2326,7 +2326,7 @@
 
 		<letterDesc letter="154">
 			<sent>
-				<date notBefore="1776-04-01" notAfter="1776-04-30">Weimar, April 1776</date>
+				<date notBefore="1776-04-07" notAfter="1776-04-30">Weimar, April 1776</date>
 				<location ref="8" />
 				<person ref="1" />
 			</sent>
@@ -2341,7 +2341,7 @@
 
 		<letterDesc letter="155">
 			<sent>
-				<date notBefore="1776-04-01" notAfter="1776-04-30">Weimar, April 1776</date>
+				<date notBefore="1776-04-07" notAfter="1776-04-30">Weimar, April 1776</date>
 				<location ref="8" />
 				<person ref="1" />
 			</sent>
@@ -2371,7 +2371,7 @@
 
 		<letterDesc letter="157">
 			<sent>
-				<date notBefore="1776-04-01" notAfter="1776-04-30">Weimar, April 1776</date>
+				<date notBefore="1776-04-07" notAfter="1776-04-30">Weimar, April 1776</date>
 				<location ref="8" />
 				<person ref="1" />
 			</sent>
@@ -2447,7 +2447,7 @@
 
 		<letterDesc letter="162">
 			<sent>
-				<date notBefore="1776-04-01" notAfter="1776-04-30">Mannheim, April 1776</date>
+				<date notBefore="1776-04-07" notAfter="1776-04-30">Mannheim, April 1776</date>
 				<location ref="31" />
 				<person ref="35" />
 			</sent>
@@ -2462,7 +2462,7 @@
 
 		<letterDesc letter="163">
 			<sent>
-				<date notAfter="1776-04-26">Weimar, Mitte April [vor dem 26. April 1776]</date>
+				<date notAfter="1776-04-15">Weimar, Mitte April [vor dem 26. April 1776]</date>
 				<location ref="8" />
 				<person ref="1" />
 			</sent>
@@ -2477,7 +2477,7 @@
 
 		<letterDesc letter="164">
 			<sent>
-				<date notBefore="1776-04-01" notAfter="1776-04-30">Weimar, April 1776</date>
+				<date notBefore="1776-04-07" notAfter="1776-04-30">Weimar, April 1776</date>
 				<location ref="8" />
 				<person ref="1" />
 			</sent>
@@ -2492,7 +2492,7 @@
 
 		<letterDesc letter="165">
 			<sent>
-				<date notBefore="1776-04-01" notAfter="1776-04-30">Weimar, April 1776</date>
+				<date notBefore="1776-04-07" notAfter="1776-04-30">Weimar, April 1776</date>
 				<location ref="8" />
 				<person ref="1" />
 			</sent>
@@ -2507,7 +2507,7 @@
 
 		<letterDesc letter="166">
 			<sent>
-				<date notBefore="1776-04-01" notAfter="1776-04-30">Weimar, April 1776</date>
+				<date notBefore="1776-04-07" notAfter="1776-04-30">Weimar, April 1776</date>
 				<location ref="8" />
 				<person ref="1" />
 			</sent>
@@ -2522,7 +2522,7 @@
 
 		<letterDesc letter="167">
 			<sent>
-				<date notBefore="1776-04-01" notAfter="1776-04-30">Weimar, April 1776</date>
+				<date notBefore="1776-04-07" notAfter="1776-04-30">Weimar, April 1776</date>
 				<location ref="8" />
 				<person ref="1" />
 			</sent>
@@ -2885,7 +2885,7 @@
 
 		<letterDesc letter="191">
 			<sent>
-				<date notBefore="1776-05-15" notAfter="1776-08-20">Weimar, Mitte 1776</date>
+				<date notBefore="1776-06-01" notAfter="1776-06-15">Weimar, Mitte 1776</date>
 				<location ref="8" />
 				<person ref="1" />
 			</sent>
@@ -3068,7 +3068,7 @@
 
 		<letterDesc letter="203">
 			<sent>
-				<date notBefore="1776-07-01" notAfter="1776-07-31">Berka, Juli 1776</date>
+				<date notBefore="1776-07-10" notAfter="1776-07-31">Berka, Juli 1776</date>
 				<location ref="14" />
 				<person ref="1" />
 			</sent>
@@ -3113,7 +3113,7 @@
 
 		<letterDesc letter="206">
 			<sent>
-				<date notBefore="1776-07-01">Berka, wahrscheinlich Juli 1776 [nach dem 23. Mai 1776]</date>
+				<date notBefore="1776-07-10">Berka, wahrscheinlich Juli 1776 [nach dem 23. Mai 1776]</date>
 				<location ref="14" />
 				<person ref="1" />
 			</sent>
@@ -3143,7 +3143,7 @@
 
 		<letterDesc letter="208">
 			<sent>
-				<date notBefore="1776-07-01" notAfter="1776-07-31">Weimar, Juli 1776</date>
+				<date notBefore="1776-07-10" notAfter="1776-07-31">Weimar, Juli 1776</date>
 				<location ref="8" />
 				<person ref="12" />
 			</sent>
@@ -3158,7 +3158,7 @@
 
 		<letterDesc letter="209">
 			<sent>
-				<date notBefore="1776-07-01" notAfter="1776-07-31">Weimar, Juli 1776</date>
+				<date notBefore="1776-07-10" notAfter="1776-07-31">Weimar, Juli 1776</date>
 				<location ref="8" />
 				<person ref="45" />
 			</sent>
@@ -3173,7 +3173,7 @@
 
 		<letterDesc letter="210">
 			<sent>
-				<date notBefore="1776-07-01" notAfter="1776-07-31">Berka, Juli 1776</date>
+				<date notBefore="1776-07-10" notAfter="1776-07-31">Berka, Juli 1776</date>
 				<location ref="14" />
 				<person ref="1" />
 			</sent>
@@ -3233,7 +3233,7 @@
 
 		<letterDesc letter="214">
 			<sent>
-				<date notBefore="1776-07-01" notAfter="1776-07-31">Berka, Juli 1776</date>
+				<date notBefore="1776-07-10" notAfter="1776-07-31">Berka, Juli 1776</date>
 				<location ref="14" />
 				<person ref="1" />
 			</sent>
@@ -3263,7 +3263,7 @@
 
 		<letterDesc letter="216">
 			<sent>
-				<date notBefore="1776-07-01" notAfter="1776-07-31">Weimar, Juli 1776</date>
+				<date notBefore="1776-07-10" notAfter="1776-07-31">Weimar, Juli 1776</date>
 				<location ref="7" />
 				<person ref="11" />
 			</sent>
@@ -3278,7 +3278,7 @@
 
 		<letterDesc letter="217">
 			<sent>
-				<date notBefore="1776-07-01" notAfter="1776-07-31">Berka, Juli 1776</date>
+				<date notBefore="1776-07-10" notAfter="1776-07-31">Berka, Juli 1776</date>
 				<location ref="14" />
 				<person ref="1" />
 			</sent>
@@ -3308,7 +3308,7 @@
 
 		<letterDesc letter="219">
 			<sent>
-				<date notBefore="1776-07-01" notAfter="1776-07-31">Berka, Juli 1776</date>
+				<date notBefore="1776-07-10" notAfter="1776-07-31">Berka, Juli 1776</date>
 				<location ref="14" />
 				<person ref="1" />
 			</sent>
@@ -3353,7 +3353,7 @@
 
 		<letterDesc letter="222">
 			<sent>
-				<date notBefore="1776-07-01" notAfter="1776-07-31">Straßburg, Juli 1776</date>
+				<date notBefore="1776-07-10" notAfter="1776-07-31">Straßburg, Juli 1776</date>
 				<location ref="7" />
 				<person ref="11" />
 			</sent>
@@ -3383,7 +3383,7 @@
 
 		<letterDesc letter="224">
 			<sent>
-				<date notBefore="1776-07-01" notAfter="1776-07-31">Berka, Juli 1776</date>
+				<date notBefore="1776-07-10" notAfter="1776-07-31">Berka, Juli 1776</date>
 				<location ref="14" />
 				<person ref="25" />
 			</sent>
@@ -3905,7 +3905,7 @@
 
 		<letterDesc letter="258">
 			<sent>
-				<date notBefore="1776-11-15" notAfter="1776-11-30">Berka, Ende November 1776</date>
+				<date notBefore="1776-11-27" notAfter="1776-11-30">Berka, Ende November 1776</date>
 				<location ref="14" />
 				<person ref="1" />
 			</sent>
@@ -5068,7 +5068,7 @@
 
 		<letterDesc letter="335">
 			<sent>
-				<date notBefore="1780-04-01" notAfter="1780-04-30">St. Petersburg, April 1780</date>
+				<date notBefore="1780-04-10" notAfter="1780-04-30">St. Petersburg, April 1780</date>
 				<location ref="46" />
 				<person ref="1" />
 			</sent>