diff --git a/CHANGELOG.md b/CHANGELOG.md
index 42e6fc20..9b8518d5 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,12 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](http://keepachangelog.com/)
 and this project adheres to [Semantic Versioning](http://semver.org/).
 
+## [Unreleased]
+
+### Fixed
+
+- Allow iterators to go out of bounds with prev - [#587](https://github.com/PHPOffice/PhpSpreadsheet/issues/587)
+
 ## [1.4.0] - 2018-08-06
 
 ### Added
diff --git a/src/PhpSpreadsheet/Worksheet/ColumnCellIterator.php b/src/PhpSpreadsheet/Worksheet/ColumnCellIterator.php
index a4cdb6f4..7e8f040d 100644
--- a/src/PhpSpreadsheet/Worksheet/ColumnCellIterator.php
+++ b/src/PhpSpreadsheet/Worksheet/ColumnCellIterator.php
@@ -153,10 +153,6 @@ class ColumnCellIterator extends CellIterator
      */
     public function prev()
     {
-        if ($this->currentRow <= $this->startRow) {
-            throw new PhpSpreadsheetException("Row is already at the beginning of range ({$this->startRow} - {$this->endRow})");
-        }
-
         do {
             --$this->currentRow;
         } while (($this->onlyExistingCells) &&
@@ -171,7 +167,7 @@ class ColumnCellIterator extends CellIterator
      */
     public function valid()
     {
-        return $this->currentRow <= $this->endRow;
+        return $this->currentRow <= $this->endRow && $this->currentRow >= $this->startRow;
     }
 
     /**
diff --git a/src/PhpSpreadsheet/Worksheet/ColumnIterator.php b/src/PhpSpreadsheet/Worksheet/ColumnIterator.php
index 6fdfe3ba..d2b57aad 100644
--- a/src/PhpSpreadsheet/Worksheet/ColumnIterator.php
+++ b/src/PhpSpreadsheet/Worksheet/ColumnIterator.php
@@ -157,14 +157,9 @@ class ColumnIterator implements \Iterator
 
     /**
      * Set the iterator to its previous value.
-     *
-     * @throws PhpSpreadsheetException
      */
     public function prev()
     {
-        if ($this->currentColumnIndex <= $this->startColumnIndex) {
-            throw new PhpSpreadsheetException('Column is already at the beginning of range (' . Coordinate::stringFromColumnIndex($this->endColumnIndex) . ' - ' . Coordinate::stringFromColumnIndex($this->endColumnIndex) . ')');
-        }
         --$this->currentColumnIndex;
     }
 
@@ -175,6 +170,6 @@ class ColumnIterator implements \Iterator
      */
     public function valid()
     {
-        return $this->currentColumnIndex <= $this->endColumnIndex;
+        return $this->currentColumnIndex <= $this->endColumnIndex && $this->currentColumnIndex >= $this->startColumnIndex;
     }
 }
diff --git a/src/PhpSpreadsheet/Worksheet/Iterator.php b/src/PhpSpreadsheet/Worksheet/Iterator.php
index 311808c0..d8797a34 100644
--- a/src/PhpSpreadsheet/Worksheet/Iterator.php
+++ b/src/PhpSpreadsheet/Worksheet/Iterator.php
@@ -25,7 +25,7 @@ class Iterator implements \Iterator
      *
      * @param Spreadsheet $subject
      */
-    public function __construct(Spreadsheet $subject = null)
+    public function __construct(Spreadsheet $subject)
     {
         // Set subject
         $this->subject = $subject;
@@ -82,6 +82,6 @@ class Iterator implements \Iterator
      */
     public function valid()
     {
-        return $this->position < $this->subject->getSheetCount();
+        return $this->position < $this->subject->getSheetCount() && $this->position >= 0;
     }
 }
diff --git a/src/PhpSpreadsheet/Worksheet/RowCellIterator.php b/src/PhpSpreadsheet/Worksheet/RowCellIterator.php
index 23d9b9fd..59ef329c 100644
--- a/src/PhpSpreadsheet/Worksheet/RowCellIterator.php
+++ b/src/PhpSpreadsheet/Worksheet/RowCellIterator.php
@@ -155,9 +155,6 @@ class RowCellIterator extends CellIterator
      */
     public function prev()
     {
-        if ($this->currentColumnIndex <= $this->startColumnIndex) {
-            throw new PhpSpreadsheetException('Column is already at the beginning of range (' . Coordinate::stringFromColumnIndex($this->endColumnIndex) . ' - ' . Coordinate::stringFromColumnIndex($this->endColumnIndex) . ')');
-        }
         do {
             --$this->currentColumnIndex;
         } while (($this->onlyExistingCells) && (!$this->worksheet->cellExistsByColumnAndRow($this->currentColumnIndex, $this->rowIndex)) && ($this->currentColumnIndex >= $this->startColumnIndex));
@@ -170,7 +167,7 @@ class RowCellIterator extends CellIterator
      */
     public function valid()
     {
-        return $this->currentColumnIndex <= $this->endColumnIndex;
+        return $this->currentColumnIndex <= $this->endColumnIndex && $this->currentColumnIndex >= $this->startColumnIndex;
     }
 
     /**
diff --git a/src/PhpSpreadsheet/Worksheet/RowIterator.php b/src/PhpSpreadsheet/Worksheet/RowIterator.php
index 70b7b8f7..433cea6a 100644
--- a/src/PhpSpreadsheet/Worksheet/RowIterator.php
+++ b/src/PhpSpreadsheet/Worksheet/RowIterator.php
@@ -152,15 +152,9 @@ class RowIterator implements \Iterator
 
     /**
      * Set the iterator to its previous value.
-     *
-     * @throws PhpSpreadsheetException
      */
     public function prev()
     {
-        if ($this->position <= $this->startRow) {
-            throw new PhpSpreadsheetException("Row is already at the beginning of range ({$this->startRow} - {$this->endRow})");
-        }
-
         --$this->position;
     }
 
@@ -171,6 +165,6 @@ class RowIterator implements \Iterator
      */
     public function valid()
     {
-        return $this->position <= $this->endRow;
+        return $this->position <= $this->endRow && $this->position >= $this->startRow;
     }
 }
diff --git a/tests/PhpSpreadsheetTests/Worksheet/ColumnCellIteratorTest.php b/tests/PhpSpreadsheetTests/Worksheet/ColumnCellIteratorTest.php
index 46880e2e..39756740 100644
--- a/tests/PhpSpreadsheetTests/Worksheet/ColumnCellIteratorTest.php
+++ b/tests/PhpSpreadsheetTests/Worksheet/ColumnCellIteratorTest.php
@@ -78,9 +78,8 @@ class ColumnCellIteratorTest extends TestCase
 
     public function testPrevOutOfRange()
     {
-        $this->expectException(\PhpOffice\PhpSpreadsheet\Exception::class);
-
         $iterator = new ColumnCellIterator($this->mockWorksheet, 'A', 2, 4);
         $iterator->prev();
+        self::assertFalse($iterator->valid());
     }
 }
diff --git a/tests/PhpSpreadsheetTests/Worksheet/ColumnIteratorTest.php b/tests/PhpSpreadsheetTests/Worksheet/ColumnIteratorTest.php
index 7285961d..04c626d1 100644
--- a/tests/PhpSpreadsheetTests/Worksheet/ColumnIteratorTest.php
+++ b/tests/PhpSpreadsheetTests/Worksheet/ColumnIteratorTest.php
@@ -77,9 +77,8 @@ class ColumnIteratorTest extends TestCase
 
     public function testPrevOutOfRange()
     {
-        $this->expectException(\PhpOffice\PhpSpreadsheet\Exception::class);
-
         $iterator = new ColumnIterator($this->mockWorksheet, 'B', 'D');
         $iterator->prev();
+        self::assertFalse($iterator->valid());
     }
 }
diff --git a/tests/PhpSpreadsheetTests/Worksheet/IteratorTest.php b/tests/PhpSpreadsheetTests/Worksheet/IteratorTest.php
new file mode 100644
index 00000000..80a2d783
--- /dev/null
+++ b/tests/PhpSpreadsheetTests/Worksheet/IteratorTest.php
@@ -0,0 +1,28 @@
+<?php
+
+namespace PhpOffice\PhpSpreadsheetTests\Worksheet;
+
+use PhpOffice\PhpSpreadsheet\Spreadsheet;
+use PhpOffice\PhpSpreadsheet\Worksheet\Iterator;
+use PhpOffice\PhpSpreadsheet\Worksheet\Worksheet;
+use PHPUnit\Framework\TestCase;
+
+class IteratorTest extends TestCase
+{
+    public function testIteratorFullRange()
+    {
+        $spreadsheet = new Spreadsheet();
+        $spreadsheet->createSheet();
+        $spreadsheet->createSheet();
+
+        $iterator = new Iterator($spreadsheet);
+        $columnIndexResult = 0;
+        self::assertEquals($columnIndexResult, $iterator->key());
+
+        foreach ($iterator as $key => $column) {
+            self::assertEquals($columnIndexResult++, $key);
+            self::assertInstanceOf(Worksheet::class, $column);
+        }
+        self::assertSame(3, $columnIndexResult);
+    }
+}
diff --git a/tests/PhpSpreadsheetTests/Worksheet/RowCellIteratorTest.php b/tests/PhpSpreadsheetTests/Worksheet/RowCellIteratorTest.php
index 9346d0a1..a10c7aa5 100644
--- a/tests/PhpSpreadsheetTests/Worksheet/RowCellIteratorTest.php
+++ b/tests/PhpSpreadsheetTests/Worksheet/RowCellIteratorTest.php
@@ -80,9 +80,8 @@ class RowCellIteratorTest extends TestCase
 
     public function testPrevOutOfRange()
     {
-        $this->expectException(\PhpOffice\PhpSpreadsheet\Exception::class);
-
         $iterator = new RowCellIterator($this->mockWorksheet, 2, 'B', 'D');
         $iterator->prev();
+        self::assertFalse($iterator->valid());
     }
 }
diff --git a/tests/PhpSpreadsheetTests/Worksheet/RowIteratorTest.php b/tests/PhpSpreadsheetTests/Worksheet/RowIteratorTest.php
index 63e26b34..cb0b12d1 100644
--- a/tests/PhpSpreadsheetTests/Worksheet/RowIteratorTest.php
+++ b/tests/PhpSpreadsheetTests/Worksheet/RowIteratorTest.php
@@ -75,9 +75,8 @@ class RowIteratorTest extends TestCase
 
     public function testPrevOutOfRange()
     {
-        $this->expectException(\PhpOffice\PhpSpreadsheet\Exception::class);
-
         $iterator = new RowIterator($this->mockWorksheet, 2, 4);
         $iterator->prev();
+        self::assertFalse($iterator->valid());
     }
 }