diff --git a/development/FORMAT b/development/FORMAT
index ccd11c95e1..be58e39970 100644
--- a/development/FORMAT
+++ b/development/FORMAT
@@ -7,6 +7,10 @@ changes happened in particular if possible. A good example would be
 
 -----------------------
 
+2018-04-18  Jürgen Spitzmüller <spitz@lyx.org>
+	* format incremented to 546: Add Landscape flex inset in Landscape module.
+	  \begin{landscape}...\end{landscape} > \begin_inset Flex Landscape
+
 2018-03-14 Yuriy Skalko <yuriy.skalko@gmail.com>
  	* Format incremented to 547: support for Charter font from XCharter package.
 
diff --git a/lib/Makefile.am b/lib/Makefile.am
index 5f55f0b692..f86b6de39a 100644
--- a/lib/Makefile.am
+++ b/lib/Makefile.am
@@ -2212,6 +2212,7 @@ dist_layouts_DATA =\
 	layouts/jss.layout \
 	layouts/kluwer.layout \
 	layouts/knitr.module \
+	layouts/landscape.module \
 	layouts/latex8.layout \
 	layouts/letter.layout \
 	layouts/lettre.layout \
diff --git a/lib/layouts/landscape.module b/lib/layouts/landscape.module
new file mode 100644
index 0000000000..15ca77be4c
--- /dev/null
+++ b/lib/layouts/landscape.module
@@ -0,0 +1,23 @@
+#\DeclareLyXModule{Landscape}
+#DescriptionBegin
+#Output parts of the document in landscape mode.
+#DescriptionEnd
+#
+#Author: Jürgen Spitzmüller <spitz@lyx.org>
+
+Format 67
+
+InsetLayout Flex:Landscape
+	LyXType		custom
+	Decoration	classic
+	ResetsFont	0
+	MultiPar	1
+	LabelString	Landscape
+	LatexName	landscape
+	LatexType	environment
+	LabelFont
+	  Family	Roman
+	  Color		red
+	EndFont
+	Requires        lscape
+End
diff --git a/lib/lyx2lyx/lyx_2_4.py b/lib/lyx2lyx/lyx_2_4.py
index 7aae4097fe..17821ec80b 100644
--- a/lib/lyx2lyx/lyx_2_4.py
+++ b/lib/lyx2lyx/lyx_2_4.py
@@ -24,16 +24,16 @@ import sys, os
 
 # Uncomment only what you need to import, please.
 
-from parser_tools import (find_end_of_inset, find_token, get_bool_value, get_value) 
+from parser_tools import (find_end_of_inset, find_end_of_layout, find_token, get_bool_value, get_value) 
 #    del_token, del_value, del_complete_lines,
-#    find_complete_lines, find_end_of, find_end_of_layout, 
+#    find_complete_lines, find_end_of, 
 #    find_re, find_substring, find_token_backwards,
 #    get_containing_inset, get_containing_layout, get_value,
 #    get_quoted_value, is_in_inset, set_bool_value
 #    find_tokens, find_token_exact, check_token, get_option_value
 
-from lyx2lyx_tools import (add_to_preamble)
-#  put_cmd_in_ert, revert_font_attrs, insert_to_preamble, latex_length
+from lyx2lyx_tools import (put_cmd_in_ert, add_to_preamble)
+#  revert_font_attrs, insert_to_preamble, latex_length
 #  get_ert, lyx2latex, lyx2verbatim, length_in_bp, convert_info_insets
 #  revert_flex_inset, hex2ratio, str2bool
 
@@ -153,6 +153,29 @@ def revert_xcharter(document):
         add_to_preamble(document, ["\\usepackage%s{XCharter}"%options])
 
 
+def revert_lscape(document):
+    " Reverts the landscape environment (Landscape module) to TeX-code "
+
+    if not "landscape" in document.get_module_list():
+        return
+
+    i = 0
+    while True:
+        i = find_token(document.body, "\\begin_inset Flex Landscape", i)
+        if i == -1:
+            return
+        j = find_end_of_inset(document.body, i)
+        if j == -1:
+            document.warning("Malformed LyX document: Can't find end of Landscape inset")
+            i += 1
+            continue
+
+        document.body[j - 2 : j + 1] = put_cmd_in_ert("\\end{landscape}")
+        document.body[i : i + 4] = put_cmd_in_ert("\\begin{landscape}")
+        add_to_preamble(document, ["\\usepackage{pdflscape}"])
+        # no need to reset i
+
+
 ##
 # Conversion hub
 #
@@ -161,10 +184,12 @@ supported_versions = ["2.4.0", "2.4"]
 convert = [
            [545, [convert_lst_literalparam]],
            [546, []],
-           [547, []]
+           [547, []],
+           [548, []]
           ]
 
 revert =  [
+           [547, [revert_lscape]],
            [546, [revert_xcharter]],
            [545, [revert_paratype]],
            [544, [revert_lst_literalparam]]
diff --git a/src/tex2lyx/TODO.txt b/src/tex2lyx/TODO.txt
index be5d770021..b108eb2822 100644
--- a/src/tex2lyx/TODO.txt
+++ b/src/tex2lyx/TODO.txt
@@ -58,6 +58,9 @@ Format LaTeX feature                        LyX feature
       \begin{btUnit}...\end{btUnit}        \multibib {none|part|chapter|section|subsection}
         (if a part, chapter, section etc.
          follows the \begin...)
+546   Landscape support
+      \begin{landscape}...\end{landscape}  \begin_inset Flex Landscape
+      with longtable content:              <features rotate ="90"...>
 
 
 
diff --git a/src/version.h b/src/version.h
index 8d136cdff4..4b5639f3b2 100644
--- a/src/version.h
+++ b/src/version.h
@@ -32,8 +32,8 @@ extern char const * const lyx_version_info;
 
 // Do not remove the comment below, so we get merge conflict in
 // independent branches. Instead add your own.
-#define LYX_FORMAT_LYX 547 // Yuriy Skalko: support for XCharter font
-#define LYX_FORMAT_TEX2LYX 547
+#define LYX_FORMAT_LYX 548 // spitz: landscape module
+#define LYX_FORMAT_TEX2LYX 548
 
 #if LYX_FORMAT_TEX2LYX != LYX_FORMAT_LYX
 #ifndef _MSC_VER