diff --git a/README.md b/README.md
index 19dc284..c690920 100644
--- a/README.md
+++ b/README.md
@@ -50,7 +50,8 @@ these PHP releases:
 * Romans `1.1.*`: PHP `^7.0` (Tiberius)
 * Romans `1.2.*`: PHP `>=7.4` (Caligula)
 * Romans `1.3.*`: PHP `>=7.4` (Claudius)
-* Romans `1.4.*`: PHP `>=8.1` (Nero)
+* Romans `1.4.*`: PHP `>=7.4` (Nero)
+* Romans `1.5.*`: PHP `>=8.0` (Galba)
 
 ## Integrations
 
@@ -154,6 +155,31 @@ $filter = new IntToRoman();
 $result = $filter->filter(0); // N
 ```
 
+### Cache
+
+This package uses [PSR-6 Caching Interface](https://www.php-fig.org/psr/psr-6)
+to improve execution, mainly over loops (like `while` or `foreach`) using cache
+libraries. Any PSR-6 implementation can be used and we suggest
+[Symfony Cache](https://packagist.org/packages/symfony/cache) package.
+
+```php
+use Romans\Filter\IntToRoman;
+use Romans\Filter\RomanToInt;
+use Symfony\Component\Cache\Adapter\ArrayAdapter;
+
+$cache = new ArrayAdapter();
+
+$filter = new RomanToInt();
+$filter->setCache($cache);
+$result = $filter->filter('MCMXCIX'); // 1999
+$result = $filter->filter('MCMXCIX'); // 1999 (from cache)
+
+$filter = new IntToRoman();
+$filter->setCache($cache);
+$result = $filter->filter(1999); // MCMXCIX
+$result = $filter->filter(1999); // MCMXCIX (from cache)
+```
+
 ## Development
 
 You can use Docker Compose to build an image and run a container to develop and
diff --git a/composer.json b/composer.json
index 5599328..00e23e8 100644
--- a/composer.json
+++ b/composer.json
@@ -25,10 +25,14 @@
   "require": {
     "php": ">=7.4"
   },
+  "suggest": {
+    "symfony/cache": "Cache results to improve performance (or any PSR-6 implementation)"
+  },
   "require-dev": {
     "php-parallel-lint/php-parallel-lint": "1.3.*",
     "phpmd/phpmd": "2.10.*",
     "phpunit/phpunit": "9.5.*",
+    "psr/cache": "1.0.*",
     "sebastian/phpcpd": "6.0.*",
     "slevomat/coding-standard": "7.0.*",
     "squizlabs/php_codesniffer": "3.6.*"
diff --git a/composer.lock b/composer.lock
index d5303ab..899de77 100644
--- a/composer.lock
+++ b/composer.lock
@@ -4,7 +4,7 @@
         "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#installing-dependencies",
         "This file is @generated automatically"
     ],
-    "content-hash": "4695b3b819edf757d0f2971ad1f97228",
+    "content-hash": "b631e238123f90c8356c25d4b328aec4",
     "packages": [],
     "packages-dev": [
         {
@@ -1329,6 +1329,55 @@
             ],
             "time": "2021-09-25T07:38:51+00:00"
         },
+        {
+            "name": "psr/cache",
+            "version": "1.0.1",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/php-fig/cache.git",
+                "reference": "d11b50ad223250cf17b86e38383413f5a6764bf8"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/php-fig/cache/zipball/d11b50ad223250cf17b86e38383413f5a6764bf8",
+                "reference": "d11b50ad223250cf17b86e38383413f5a6764bf8",
+                "shasum": ""
+            },
+            "require": {
+                "php": ">=5.3.0"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "1.0.x-dev"
+                }
+            },
+            "autoload": {
+                "psr-4": {
+                    "Psr\\Cache\\": "src/"
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "PHP-FIG",
+                    "homepage": "http://www.php-fig.org/"
+                }
+            ],
+            "description": "Common interface for caching libraries",
+            "keywords": [
+                "cache",
+                "psr",
+                "psr-6"
+            ],
+            "support": {
+                "source": "https://github.com/php-fig/cache/tree/master"
+            },
+            "time": "2016-08-06T20:24:11+00:00"
+        },
         {
             "name": "psr/container",
             "version": "1.1.1",
diff --git a/src/Cache/CacheAwareTrait.php b/src/Cache/CacheAwareTrait.php
new file mode 100644
index 0000000..9236c6a
--- /dev/null
+++ b/src/Cache/CacheAwareTrait.php
@@ -0,0 +1,47 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Romans\Cache;
+
+use Psr\Cache\CacheItemPoolInterface as CacheInterface;
+
+/**
+ * Cache Aware Trait
+ */
+trait CacheAwareTrait
+{
+    private ?CacheInterface $cache = null;
+
+    /**
+     * Has Cache?
+     *
+     * @return bool Cache Exists
+     */
+    public function hasCache(): bool
+    {
+        return $this->cache !== null;
+    }
+
+    /**
+     * Set Cache
+     *
+     * @param ?CacheInterface $cache Cache Object
+     * @param self            Fluent Interface
+     */
+    public function setCache(?CacheInterface $cache): self
+    {
+        $this->cache = $cache;
+        return $this;
+    }
+
+    /**
+     * Get Cache
+     *
+     * @return ?CacheInterface Cache Object
+     */
+    public function getCache(): ?CacheInterface
+    {
+        return $this->cache;
+    }
+}
diff --git a/src/Filter/IntToRoman.php b/src/Filter/IntToRoman.php
index 5cda8b8..463dc40 100644
--- a/src/Filter/IntToRoman.php
+++ b/src/Filter/IntToRoman.php
@@ -4,6 +4,7 @@
 
 namespace Romans\Filter;
 
+use Romans\Cache\CacheAwareTrait;
 use Romans\Grammar\Grammar;
 use Romans\Grammar\GrammarAwareTrait;
 
@@ -12,6 +13,7 @@
  */
 class IntToRoman
 {
+    use CacheAwareTrait;
     use GrammarAwareTrait;
 
     /**
@@ -24,6 +26,20 @@ public function __construct(?Grammar $grammar = null)
         $this->setGrammar($grammar ?? new Grammar());
     }
 
+    /**
+     * Helper to Cache a Result from Value
+     *
+     * @param int    $value Integer
+     * @param string Roman Number Result
+     */
+    private function cache(int $value, string $result): void
+    {
+        if ($this->hasCache()) {
+            $item = $this->getCache()->getItem($value)->set($result);
+            $this->getCache()->save($item);
+        }
+    }
+
     /**
      * Filter Integer to Roman Number
      *
@@ -36,29 +52,32 @@ public function filter(int $value): string
             throw new Exception(sprintf('Invalid integer: %d', $value), Exception::INVALID_INTEGER);
         }
 
+        if ($this->hasCache() && $this->getCache()->hasItem($value)) {
+            return $this->getCache()->getItem($value)->get();
+        }
+
         $tokens = $this->getGrammar()->getTokens();
         $values = array_reverse($this->getGrammar()->getValuesWithModifiers(), true /* preserve keys */);
         $result = '';
 
         if ($value === 0) {
             $dataset = $values[0];
+            $result  = array_reduce($dataset, fn($result, $token) => $result . $tokens[$token], $result);
 
-            foreach ($dataset as $token) {
-                $result = $result . $tokens[$token];
-            }
+            $this->cache($value, $result);
 
             return $result;
         }
 
         foreach ($values as $current => $dataset) {
             while ($current > 0 && $value >= $current) {
-                $value = $value - $current;
-                foreach ($dataset as $token) {
-                    $result = $result . $tokens[$token];
-                }
+                $value  = $value - $current;
+                $result = array_reduce($dataset, fn($result, $token) => $result . $tokens[$token], $result);
             }
         }
 
+        $this->cache($value, $result);
+
         return $result;
     }
 }
diff --git a/src/Filter/RomanToInt.php b/src/Filter/RomanToInt.php
index 68519b7..fee72e9 100644
--- a/src/Filter/RomanToInt.php
+++ b/src/Filter/RomanToInt.php
@@ -4,6 +4,7 @@
 
 namespace Romans\Filter;
 
+use Romans\Cache\CacheAwareTrait;
 use Romans\Grammar\Grammar;
 use Romans\Lexer\Lexer;
 use Romans\Parser\Parser;
@@ -13,6 +14,8 @@
  */
 class RomanToInt
 {
+    use CacheAwareTrait;
+
     /**
      * Lexer
      */
@@ -89,6 +92,17 @@ public function getParser(): Parser
      */
     public function filter(string $value): int
     {
-        return $this->getParser()->parse($this->getLexer()->tokenize($value));
+        if ($this->hasCache() && $this->getCache()->hasItem($value)) {
+            return $this->getCache()->getItem($value)->get();
+        }
+
+        $result = $this->getParser()->parse($this->getLexer()->tokenize($value));
+
+        if ($this->hasCache()) {
+            $item = $this->getCache()->getItem($value)->set($result);
+            $this->getCache()->save($item);
+        }
+
+        return $result;
     }
 }
diff --git a/test/Cache/CacheAwareTraitTest.php b/test/Cache/CacheAwareTraitTest.php
new file mode 100644
index 0000000..9822f37
--- /dev/null
+++ b/test/Cache/CacheAwareTraitTest.php
@@ -0,0 +1,35 @@
+<?php
+
+declare(strict_types=1);
+
+namespace RomansTest\Cache;
+
+use PHPUnit\Framework\TestCase;
+use Psr\Cache\CacheItemPoolInterface as CacheInterface;
+use Romans\Cache\CacheAwareTrait;
+
+/**
+ * Cache Aware Trait Test
+ */
+class CacheAwareTraitTest extends TestCase
+{
+    /**
+     * Test Cache
+     */
+    public function testCache(): void
+    {
+        $cache   = $this->createMock(CacheInterface::class);
+        $element = $this->getMockForTrait(CacheAwareTrait::class);
+
+        $this->assertNull($element->getCache());
+        $this->assertFalse($element->hasCache());
+
+        $this->assertSame($element, $element->setCache($cache));
+        $this->assertSame($cache, $element->getCache());
+        $this->assertTrue($element->hasCache());
+
+        $this->assertSame($element, $element->setCache(null));
+        $this->assertNull($element->getCache());
+        $this->assertFalse($element->hasCache());
+    }
+}
diff --git a/test/Filter/IntToRomanTest.php b/test/Filter/IntToRomanTest.php
index 116cf22..08f2b54 100644
--- a/test/Filter/IntToRomanTest.php
+++ b/test/Filter/IntToRomanTest.php
@@ -5,6 +5,8 @@
 namespace RomansTest\Filter;
 
 use PHPUnit\Framework\TestCase;
+use Psr\Cache\CacheItemInterface as CacheItemInterface;
+use Psr\Cache\CacheItemPoolInterface as CacheInterface;
 use Romans\Filter\Exception as FilterException;
 use Romans\Filter\IntToRoman;
 use Romans\Grammar\Grammar;
@@ -80,4 +82,60 @@ public function testFilterWithNegative(): void
 
         $this->filter->filter(-1);
     }
+
+    /**
+     * Test Cache Found
+     */
+    public function testCacheFound(): void
+    {
+        $item  = $this->createMock(CacheItemInterface::class);
+        $cache = $this->createMock(CacheInterface::class);
+
+        $item->expects($this->once())
+            ->method('get')
+            ->willReturn('I');
+
+        $cache->method('hasItem')
+            ->with($this->equalTo('1'))
+            ->willReturn(true);
+
+        $cache->expects($this->once())
+            ->method('getItem')
+            ->willReturn($item);
+
+        $this->filter->setCache($cache);
+
+        $this->assertSame('I', $this->filter->filter(1));
+    }
+
+    /**
+     * Test Cache not Found
+     */
+    public function testCacheNotFound(): void
+    {
+        $item  = $this->createMock(CacheItemInterface::class);
+        $cache = $this->createMock(CacheInterface::class);
+
+        $item->expects($this->once())
+            ->method('set')
+            ->with($this->equalTo('I'))
+            ->willReturnSelf();
+
+        $cache->method('hasItem')
+            ->with($this->equalTo('1'))
+            ->willReturn(false);
+
+        $cache->expects($this->once())
+            ->method('getItem')
+            ->willReturn($item);
+
+        $cache->expects($this->once())
+            ->method('save')
+            ->with($this->equalTo($item))
+            ->willReturn(true);
+
+        $this->filter->setCache($cache);
+
+        $this->assertSame('I', $this->filter->filter(1));
+    }
 }
diff --git a/test/Filter/RomanToIntTest.php b/test/Filter/RomanToIntTest.php
index 2c77716..0c15b4e 100644
--- a/test/Filter/RomanToIntTest.php
+++ b/test/Filter/RomanToIntTest.php
@@ -5,6 +5,8 @@
 namespace RomansTest\Filter;
 
 use PHPUnit\Framework\TestCase;
+use Psr\Cache\CacheItemInterface as CacheItemInterface;
+use Psr\Cache\CacheItemPoolInterface as CacheInterface;
 use Romans\Filter\RomanToInt;
 use Romans\Grammar\Grammar;
 use Romans\Lexer\Lexer;
@@ -104,4 +106,60 @@ public function testFilterWithZero(): void
     {
         $this->assertSame(0, $this->filter->filter('N'));
     }
+
+    /**
+     * Test Cache Found
+     */
+    public function testCacheFound(): void
+    {
+        $item  = $this->createMock(CacheItemInterface::class);
+        $cache = $this->createMock(CacheInterface::class);
+
+        $item->expects($this->once())
+            ->method('get')
+            ->willReturn(1);
+
+        $cache->method('hasItem')
+            ->with($this->equalTo('I'))
+            ->willReturn(true);
+
+        $cache->expects($this->once())
+            ->method('getItem')
+            ->willReturn($item);
+
+        $this->filter->setCache($cache);
+
+        $this->assertSame(1, $this->filter->filter('I'));
+    }
+
+    /**
+     * Test Cache not Found
+     */
+    public function testCacheNotFound(): void
+    {
+        $item  = $this->createMock(CacheItemInterface::class);
+        $cache = $this->createMock(CacheInterface::class);
+
+        $item->expects($this->once())
+            ->method('set')
+            ->with($this->equalTo(1))
+            ->willReturnSelf();
+
+        $cache->method('hasItem')
+            ->with($this->equalTo('I'))
+            ->willReturn(false);
+
+        $cache->expects($this->once())
+            ->method('getItem')
+            ->willReturn($item);
+
+        $cache->expects($this->once())
+            ->method('save')
+            ->with($this->equalTo($item))
+            ->willReturn(true);
+
+        $this->filter->setCache($cache);
+
+        $this->assertSame(1, $this->filter->filter('I'));
+    }
 }