diff --git a/src/script/api/ai/ai_date.hpp.sq b/src/script/api/ai/ai_date.hpp.sq
index 3210a6950f..7bdf9519d6 100644
--- a/src/script/api/ai/ai_date.hpp.sq
+++ b/src/script/api/ai/ai_date.hpp.sq
@@ -21,6 +21,9 @@ void SQAIDate_Register(Squirrel *engine)
 	SQAIDate.PreRegister(engine);
 	SQAIDate.AddConstructor<void (ScriptDate::*)(), 1>(engine, "x");
 
+	SQAIDate.DefSQConst(engine, ScriptDate::DATE_INVALID, "DATE_INVALID");
+
+	SQAIDate.DefSQStaticMethod(engine, &ScriptDate::IsValidDate,    "IsValidDate",    2, ".i");
 	SQAIDate.DefSQStaticMethod(engine, &ScriptDate::GetCurrentDate, "GetCurrentDate", 1, ".");
 	SQAIDate.DefSQStaticMethod(engine, &ScriptDate::GetYear,        "GetYear",        2, ".i");
 	SQAIDate.DefSQStaticMethod(engine, &ScriptDate::GetMonth,       "GetMonth",       2, ".i");
diff --git a/src/script/api/ai_changelog.hpp b/src/script/api/ai_changelog.hpp
index a40996c0f8..5c9baa616a 100644
--- a/src/script/api/ai_changelog.hpp
+++ b/src/script/api/ai_changelog.hpp
@@ -20,6 +20,8 @@
  * 1.4.0 is not yet released. The following changes are not set in stone yet.
  *
  * API additions:
+ * \li AIDate::DATE_INVALID
+ * \li AIDate::IsValidDate
  * \li AIStation::HasCargoRating
  * \li AITile::GetTerrainType
  * \li AITown::FoundTown
diff --git a/src/script/api/game/game_date.hpp.sq b/src/script/api/game/game_date.hpp.sq
index 43af86afa7..dc40989da0 100644
--- a/src/script/api/game/game_date.hpp.sq
+++ b/src/script/api/game/game_date.hpp.sq
@@ -21,6 +21,9 @@ void SQGSDate_Register(Squirrel *engine)
 	SQGSDate.PreRegister(engine);
 	SQGSDate.AddConstructor<void (ScriptDate::*)(), 1>(engine, "x");
 
+	SQGSDate.DefSQConst(engine, ScriptDate::DATE_INVALID, "DATE_INVALID");
+
+	SQGSDate.DefSQStaticMethod(engine, &ScriptDate::IsValidDate,    "IsValidDate",    2, ".i");
 	SQGSDate.DefSQStaticMethod(engine, &ScriptDate::GetCurrentDate, "GetCurrentDate", 1, ".");
 	SQGSDate.DefSQStaticMethod(engine, &ScriptDate::GetYear,        "GetYear",        2, ".i");
 	SQGSDate.DefSQStaticMethod(engine, &ScriptDate::GetMonth,       "GetMonth",       2, ".i");
diff --git a/src/script/api/game_changelog.hpp b/src/script/api/game_changelog.hpp
index 20a28edcde..4ce3205143 100644
--- a/src/script/api/game_changelog.hpp
+++ b/src/script/api/game_changelog.hpp
@@ -21,6 +21,8 @@
  *
  * API additions:
  * \li GSCompany::ChangeBankBalance
+ * \li GSDate::DATE_INVALID
+ * \li GSDate::IsValidDate
  * \li GSGoal::GT_STORY_PAGE
  * \li GSGoal::IsCompleted
  * \li GSGoal::SetCompleted
diff --git a/src/script/api/script_basestation.cpp b/src/script/api/script_basestation.cpp
index d46d717a0c..5134243a96 100644
--- a/src/script/api/script_basestation.cpp
+++ b/src/script/api/script_basestation.cpp
@@ -52,9 +52,9 @@
 	return ::BaseStation::Get(station_id)->xy;
 }
 
-/* static */ int32 ScriptBaseStation::GetConstructionDate(StationID station_id)
+/* static */ ScriptDate::Date ScriptBaseStation::GetConstructionDate(StationID station_id)
 {
-	if (!IsValidBaseStation(station_id)) return -1;
+	if (!IsValidBaseStation(station_id)) return ScriptDate::DATE_INVALID;
 
-	return ::BaseStation::Get(station_id)->build_date;
+	return (ScriptDate::Date)::BaseStation::Get(station_id)->build_date;
 }
diff --git a/src/script/api/script_basestation.hpp b/src/script/api/script_basestation.hpp
index e610280790..9676829f67 100644
--- a/src/script/api/script_basestation.hpp
+++ b/src/script/api/script_basestation.hpp
@@ -13,6 +13,7 @@
 #define SCRIPT_BASESTATION_HPP
 
 #include "script_text.hpp"
+#include "script_date.hpp"
 
 /**
  * Base class for stations and waypoints.
@@ -73,7 +74,7 @@ public:
 	 * @param station_id The station to look at.
 	 * @return The last date some part of this station was build.
 	 */
-	static int32 GetConstructionDate(StationID station_id);
+	static ScriptDate::Date GetConstructionDate(StationID station_id);
 };
 
 #endif /* SCRIPT_BASESTATION_HPP */
diff --git a/src/script/api/script_date.cpp b/src/script/api/script_date.cpp
index 1f80b40d7e..6ff92debac 100644
--- a/src/script/api/script_date.cpp
+++ b/src/script/api/script_date.cpp
@@ -14,45 +14,50 @@
 #include "script_date.hpp"
 #include "../../date_func.h"
 
-/* static */ int32 ScriptDate::GetCurrentDate()
+/* static */ bool ScriptDate::IsValidDate(Date date)
 {
-	return ::_date;
+	return date >= 0;
 }
 
-/* static */ int32 ScriptDate::GetYear(int32 date)
+/* static */ ScriptDate::Date ScriptDate::GetCurrentDate()
 {
-	if (date < 0) return -1;
+	return (ScriptDate::Date)_date;
+}
+
+/* static */ int32 ScriptDate::GetYear(ScriptDate::Date date)
+{
+	if (date < 0) return DATE_INVALID;
 
 	::YearMonthDay ymd;
 	::ConvertDateToYMD(date, &ymd);
 	return ymd.year;
 }
 
-/* static */ int32 ScriptDate::GetMonth(int32 date)
+/* static */ int32 ScriptDate::GetMonth(ScriptDate::Date date)
 {
-	if (date < 0) return -1;
+	if (date < 0) return DATE_INVALID;
 
 	::YearMonthDay ymd;
 	::ConvertDateToYMD(date, &ymd);
 	return ymd.month + 1;
 }
 
-/* static */ int32 ScriptDate::GetDayOfMonth(int32 date)
+/* static */ int32 ScriptDate::GetDayOfMonth(ScriptDate::Date date)
 {
-	if (date < 0) return -1;
+	if (date < 0) return DATE_INVALID;
 
 	::YearMonthDay ymd;
 	::ConvertDateToYMD(date, &ymd);
 	return ymd.day;
 }
 
-/* static */ int32 ScriptDate::GetDate(int32 year, int32 month, int32 day_of_month)
+/* static */ ScriptDate::Date ScriptDate::GetDate(int32 year, int32 month, int32 day_of_month)
 {
-	if (month < 1 || month > 12) return -1;
-	if (day_of_month < 1 || day_of_month > 31) return -1;
-	if (year < 0 || year > MAX_YEAR) return -1;
+	if (month < 1 || month > 12) return DATE_INVALID;
+	if (day_of_month < 1 || day_of_month > 31) return DATE_INVALID;
+	if (year < 0 || year > MAX_YEAR) return DATE_INVALID;
 
-	return ::ConvertYMDToDate(year, month - 1, day_of_month);
+	return (ScriptDate::Date)::ConvertYMDToDate(year, month - 1, day_of_month);
 }
 
 /* static */ int32 ScriptDate::GetSystemTime()
diff --git a/src/script/api/script_date.hpp b/src/script/api/script_date.hpp
index 488e35edae..b402b0a2b2 100644
--- a/src/script/api/script_date.hpp
+++ b/src/script/api/script_date.hpp
@@ -13,6 +13,7 @@
 #define SCRIPT_DATE_HPP
 
 #include "script_object.hpp"
+#include "../../date_type.h"
 
 /**
  * Class that handles all date related (calculation) functions.
@@ -27,6 +28,21 @@
  */
 class ScriptDate : public ScriptObject {
 public:
+	/**
+	 * Date data type is an integer value. Use ScriptDate::GetDate to
+	 * compose valid date values for a known year, month and day.
+	 */
+	enum Date {
+		DATE_INVALID = ::INVALID_DATE, ///< A value representing an invalid date.
+	};
+
+	/**
+	 * Validates if a date value represent a valid date.
+	 * @param date The date to validate.
+	 * @return True if the date is valid, otherwise false
+	 */
+	static bool IsValidDate(Date date);
+
 	/**
 	 * Get the current date.
 	 * This is the number of days since epoch under the assumption that
@@ -34,28 +50,28 @@ public:
 	 *  100 but not by 400.
 	 * @return The current date.
 	 */
-	static int32 GetCurrentDate();
+	static Date GetCurrentDate();
 
 	/**
 	 * Get the year of the given date.
 	 * @param date The date to get the year of.
 	 * @return The year.
 	 */
-	static int32 GetYear(int32 date);
+	static int32 GetYear(Date date);
 
 	/**
 	 * Get the month of the given date.
 	 * @param date The date to get the month of.
 	 * @return The month.
 	 */
-	static int32 GetMonth(int32 date);
+	static int32 GetMonth(Date date);
 
 	/**
 	 * Get the day (of the month) of the given date.
 	 * @param date The date to get the day of.
 	 * @return The day.
 	 */
-	static int32 GetDayOfMonth(int32 date);
+	static int32 GetDayOfMonth(Date date);
 
 	/**
 	 * Get the date given a year, month and day of month.
@@ -64,7 +80,7 @@ public:
 	 * @param day_of_month The day of month of the to-be determined date.
 	 * @return The date.
 	 */
-	static int32 GetDate(int32 year, int32 month, int32 day_of_month);
+	static Date GetDate(int32 year, int32 month, int32 day_of_month);
 
 	/**
 	 * Get the time of the host system.
diff --git a/src/script/api/script_engine.cpp b/src/script/api/script_engine.cpp
index a34d0910f3..138628547b 100644
--- a/src/script/api/script_engine.cpp
+++ b/src/script/api/script_engine.cpp
@@ -171,11 +171,11 @@
 	return ::Engine::Get(engine_id)->GetDisplayMaxTractiveEffort();
 }
 
-/* static */ int32 ScriptEngine::GetDesignDate(EngineID engine_id)
+/* static */ ScriptDate::Date ScriptEngine::GetDesignDate(EngineID engine_id)
 {
-	if (!IsValidEngine(engine_id)) return -1;
+	if (!IsValidEngine(engine_id)) return ScriptDate::DATE_INVALID;
 
-	return ::Engine::Get(engine_id)->intro_date;
+	return (ScriptDate::Date)::Engine::Get(engine_id)->intro_date;
 }
 
 /* static */ ScriptVehicle::VehicleType ScriptEngine::GetVehicleType(EngineID engine_id)
diff --git a/src/script/api/script_engine.hpp b/src/script/api/script_engine.hpp
index 058d23082c..5f703e159d 100644
--- a/src/script/api/script_engine.hpp
+++ b/src/script/api/script_engine.hpp
@@ -15,6 +15,7 @@
 #include "script_vehicle.hpp"
 #include "script_rail.hpp"
 #include "script_airport.hpp"
+#include "script_date.hpp"
 
 /**
  * Class that handles all engine related functions.
@@ -174,7 +175,7 @@ public:
 	 * @pre IsValidEngine(engine_id).
 	 * @return The date this engine was designed.
 	 */
-	static int32 GetDesignDate(EngineID engine_id);
+	static ScriptDate::Date GetDesignDate(EngineID engine_id);
 
 	/**
 	 * Get the type of an engine.
diff --git a/src/script/api/script_story_page.cpp b/src/script/api/script_story_page.cpp
index 034cfdf2a6..17b7b82736 100644
--- a/src/script/api/script_story_page.cpp
+++ b/src/script/api/script_story_page.cpp
@@ -132,14 +132,15 @@
 	return company;
 }
 
-/* static */ int32 ScriptStoryPage::GetDate(StoryPageID story_page_id)
+/* static */ ScriptDate::Date ScriptStoryPage::GetDate(StoryPageID story_page_id)
 {
-	EnforcePrecondition(-1, IsValidStoryPage(story_page_id));
+	EnforcePrecondition(ScriptDate::DATE_INVALID, IsValidStoryPage(story_page_id));
+	EnforcePrecondition(ScriptDate::DATE_INVALID, ScriptObject::GetCompany() == OWNER_DEITY);
 
-	return StoryPage::Get(story_page_id)->date;
+	return (ScriptDate::Date)StoryPage::Get(story_page_id)->date;
 }
 
-/* static */ bool ScriptStoryPage::SetDate(StoryPageID story_page_id, int32 date)
+/* static */ bool ScriptStoryPage::SetDate(StoryPageID story_page_id, ScriptDate::Date date)
 {
 	EnforcePrecondition(false, IsValidStoryPage(story_page_id));
 	EnforcePrecondition(false, ScriptObject::GetCompany() == OWNER_DEITY);
diff --git a/src/script/api/script_story_page.hpp b/src/script/api/script_story_page.hpp
index 49d4a639a6..c22d4c198e 100644
--- a/src/script/api/script_story_page.hpp
+++ b/src/script/api/script_story_page.hpp
@@ -13,6 +13,7 @@
 #define SCRIPT_STORY_HPP
 
 #include "script_company.hpp"
+#include "script_date.hpp"
 #include "../../story_type.h"
 #include "../../story_base.h"
 
@@ -154,17 +155,17 @@ public:
 	 * @return The date
 	 * @pre IsValidStoryPage(story_page_id).
 	 */
-	static int32 GetDate(StoryPageID story_page_id);
+	static ScriptDate::Date GetDate(StoryPageID story_page_id);
 
 	/**
 	 * Update date of a story page. The date is shown in the top left of the page
 	 * @param story_page_id The story page to set the date for.
-	 * @param date Page date (@see ScriptDate)
+	 * @param date Date to display at the top of story page or ScriptDate::DATE_INVALID to disable showing date on this page. (also, @see ScriptDate)
 	 * @return True if the action succeeded.
 	 * @pre No ScriptCompanyMode may be in scope.
 	 * @pre IsValidStoryPage(story_page_id).
 	 */
-	static bool SetDate(StoryPageID story_page_id, int32 date);
+	static bool SetDate(StoryPageID story_page_id, ScriptDate::Date date);
 
 	/**
 	 * Update title of a story page. The title is shown in the page selector drop down.
diff --git a/src/script/api/script_subsidy.cpp b/src/script/api/script_subsidy.cpp
index 8ec074d4d0..146ba690d4 100644
--- a/src/script/api/script_subsidy.cpp
+++ b/src/script/api/script_subsidy.cpp
@@ -48,9 +48,9 @@
 	return (ScriptCompany::CompanyID)((byte)::Subsidy::Get(subsidy_id)->awarded);
 }
 
-/* static */ int32 ScriptSubsidy::GetExpireDate(SubsidyID subsidy_id)
+/* static */ ScriptDate::Date ScriptSubsidy::GetExpireDate(SubsidyID subsidy_id)
 {
-	if (!IsValidSubsidy(subsidy_id)) return -1;
+	if (!IsValidSubsidy(subsidy_id)) return ScriptDate::DATE_INVALID;
 
 	int year = ScriptDate::GetYear(ScriptDate::GetCurrentDate());
 	int month = ScriptDate::GetMonth(ScriptDate::GetCurrentDate());
diff --git a/src/script/api/script_subsidy.hpp b/src/script/api/script_subsidy.hpp
index 3069ad918f..16a6794409 100644
--- a/src/script/api/script_subsidy.hpp
+++ b/src/script/api/script_subsidy.hpp
@@ -13,6 +13,7 @@
 #define SCRIPT_SUBSIDY_HPP
 
 #include "script_company.hpp"
+#include "script_date.hpp"
 
 /**
  * Class that handles all subsidy related functions.
@@ -83,7 +84,7 @@ public:
 	 * @note The return value of this function will change if the subsidy is
 	 *  awarded.
 	 */
-	static int32 GetExpireDate(SubsidyID subsidy_id);
+	static ScriptDate::Date GetExpireDate(SubsidyID subsidy_id);
 
 	/**
 	 * Get the cargo type that has to be transported in order to be awarded this
diff --git a/src/script/api/template/template_date.hpp.sq b/src/script/api/template/template_date.hpp.sq
index 976ddb7a50..cca4a258b1 100644
--- a/src/script/api/template/template_date.hpp.sq
+++ b/src/script/api/template/template_date.hpp.sq
@@ -12,6 +12,10 @@
 #include "../script_date.hpp"
 
 namespace SQConvert {
+	/* Allow enums to be used as Squirrel parameters */
+	template <> inline ScriptDate::Date GetParam(ForceType<ScriptDate::Date>, HSQUIRRELVM vm, int index, SQAutoFreePointers *ptr) { SQInteger tmp; sq_getinteger(vm, index, &tmp); return (ScriptDate::Date)tmp; }
+	template <> inline int Return<ScriptDate::Date>(HSQUIRRELVM vm, ScriptDate::Date res) { sq_pushinteger(vm, (int32)res); return 1; }
+
 	/* Allow ScriptDate to be used as Squirrel parameter */
 	template <> inline ScriptDate *GetParam(ForceType<ScriptDate *>, HSQUIRRELVM vm, int index, SQAutoFreePointers *ptr) { SQUserPointer instance; sq_getinstanceup(vm, index, &instance, 0); return  (ScriptDate *)instance; }
 	template <> inline ScriptDate &GetParam(ForceType<ScriptDate &>, HSQUIRRELVM vm, int index, SQAutoFreePointers *ptr) { SQUserPointer instance; sq_getinstanceup(vm, index, &instance, 0); return *(ScriptDate *)instance; }
diff --git a/src/story_gui.cpp b/src/story_gui.cpp
index 9f84e57b0a..872ed0a9a2 100644
--- a/src/story_gui.cpp
+++ b/src/story_gui.cpp
@@ -519,8 +519,10 @@ public:
 		int y_offset = - this->vscroll->GetPosition();
 
 		/* Date */
-		SetDParam(0, page->date);
-		DrawString(0, right - x, y_offset, STR_JUST_DATE_LONG, TC_BLACK);
+		if (page->date != INVALID_DATE) {
+			SetDParam(0, page->date);
+			DrawString(0, right - x, y_offset, STR_JUST_DATE_LONG, TC_BLACK);
+		}
 		y_offset += line_height;
 
 		/* Title */